Would you spend the night here?

Nestled under a Swedish town, Sala Silver Mine once hosted a bedroom 155 meters (509 feet) beneath the surface – long touted as the “world’s deepest hotel suite.” For adventurous souls, it offered a night in a rock-cut chamber lit by candle and chandelier, as misted breaths mingled with the drip of distant water. In that silence a kind of magic lingered: the chill of 2°C tunnels giving way to a snug 18–19°C in the heated suite. This guide is a complete update (2024) to that story – it opens with the mine suite’s surprising closure, then turns to four centuries of mining history, vivid accounts of the subterranean stay, today’s tours and accommodations, and finally, comparable unique lodgings worldwide.

After more than a decade offering the public a slice of underground luxury, the Sala Silver Mine suite is no longer available. In 2024 the operators announced the booking program was permanently discontinued, and the chamber is now used for storage. The mine itself remains open as a museum and activity center.

Current status (as of 2024)

What Was the Sala Silver Mine Hotel Suite?

The World’s Deepest Hotel Room

Sala Silver Mine’s subterranean “suite” was literally carved out of history. In an excavated chamber at 155 meters depth (508 feet), guests once stepped into what felt like an underground Victorian parlor. Silver and rock walls framed a double bed flanked by oil-filled lanterns and brass chandeliers; a fully-stocked bar and ice-filled cold cellar offered Champagne on ice. A personal host guided the overnight stay (which always followed a guided mine tour), delivering a gourmet dinner and breakfast made from local Swedish ingredients. By one account, the host would descend nightly to spread the morning table, then re-emerge at dawn, leaving the loved-up couple to wake by candlelight in peace.

This was no rustic camping trip: the chamber had electric lighting and heating, power courtesy of a freight elevator that connected the innermost depths to the surface. Still, the adventure was absolute. Heavy boots and jackets were swapped for sleeping wraps before lights-out; cell phones never made it down (guests used an intercom system to reach staff on the surface). The surreal isolation meant guests had the entire mine to themselves overnight – save for their host and the echoes of history. (Rattling the ancient iron ladder or puddle water nearby, one could almost imagine miners’ footsteps from centuries past.) In its prime, Sala Silvergruva’s suite boasted the official title “world’s deepest hotel room,” a claim reflecting the 155m descent required to reach it.

Carved out between 2007 and 2014, the 18m × 6m hall was created using the old “fire-setting” technique – alternating fires and cold water to crack the granite, just as miners did 300 years ago. Even in the 2000s, this method of excavation was used to minimize vibrations to the surrounding 400-year-old tunnels.

Historical Note

Location and Access

Sala Silvergruva (Sala Silver Mine) sits in the Västmanland region of Sweden, about 120 km northwest of Stockholm. The suite’s entrance was not a hole in the wilderness, but an unused ore shaft open to visitors at the mine’s museum complex. Guests reached the chamber via a freight-style elevator (the Queen Christina shaft), riding in complete darkness as the rock slid by outside. The entire descent took roughly two minutes, with temperature dropping steadily. (By 60 meters below, the lift cabin is so deep that only minimal light from above peeks in. The photo below, taken at the 60m level on a tour, hints at that ride into darkness.)

Once at 155m, metal steps and small platforms led the rest of the way down to the suite’s doorway. The air was still and chilly. Tour guides note a “warm pocket” created by the suite’s heaters that visitors immediately feel upon entry, a stark contrast to the roughly 2°C ambient temperature throughout the rest of the mine. Guests would have their bags and dinner supplied from above; after time passed under the rock, a second elevator trip in the morning returned the couple to daylight.

The Suite’s Unique Features

Inside, the suite was furnished like a high-end hotel room with a bizarre twist. Hand-carved silver tableware and Swarovski crystal glassware (mined in nearby Sweden) reinforced the theme of opulence amid salt mines of darkness. Soft carpeting covered parts of the rough stone floor. Even the bathroom arrangement was eccentric: originally there was no toilet in the chamber at all (guests had to venture out with a portable toilet to a tunnel outside). Only in recent years did staff install a proper flush toilet inside the mine, a nod to comfort without ruining the adventure. (The management gratefully notes this improvement in their TripAdvisor responses.)

Another hallmark was digital detox. With zero cell coverage deep underground, couples were truly unplugged. Instead of distractions, the suite offered games and books, plus an “emergency button” on the phone connecting via intercom to surface hosts. Elsewhere in the mine, guides have reported that a few rooms are equipped with hidden wi-fi for staff use, but none of it was available to guests. One longtime mine ranger says this isolation – the gentle echo of droplets, the hush of deep night – is exactly what made the experience remarkable.

Guests also prized small touches: thick wool blankets to stave off cold, local honey with tea for midnight warmth, and even the suite’s bear cub mascot – a stuffed teddy which guests could keep as a memento. By all accounts, a night underground was surprising cozy. (Some travelers joked it felt like a scene from Dracula – an oddity the mine’s marketing rather encouraged!) In truth, the suite was an imaginative blend of industrial heritage and boutique luxury. No other hotel on earth offered quite this combination of setting and exclusivity.

The Complete History of Sala Silver Mine

Sala Silver Mine boasts a history stretching back over 400 years. Legend has it that silver was first found near Sala in the 15th century, and by the late 1500s the mine was delivering wealth to the Swedish crown. In those early days, Sala (then a tiny village) surged into importance – King Gustavus Adolphus even granted the town its charter in 1624. By some counts, Sala produced over 200 million ounces of silver in its lifetime, and routinely employed thousands of miners at its peak. (Indeed, the shafts around Sala were so rich that in Polish records the mine was known as ‘Sveriges skattkista’ – Sweden’s treasure chest.)

The mine’s extent was vast: at maximum, Sala reached nearly 320 meters deep, its tunnels branching for many kilometers. (One source notes over 20 km of excavated drifts by the 20th century.) Early mining was done by hand and horse – miners would smash ore by spiking it with pickaxes and then hauling it to surface via winding gear and pulleys. In the 18th and 19th centuries, technological advances like blasting, pump systems and mechanized ore processing extended Sala’s life. Still, the ore gradually ran out. By 1908 the financial burdens of deep mining forced closure of the old silver operations.

Mining did briefly resume during World War II for lead and zinc, but Sala’s real transformation came post-1962. After one last wave of extraction ended in the 1960s, the mine was mothballed. For over two decades it lay quiet, a subterranean relic. Then in 1988 the municipality of Sala took ownership and reopened it as a show mine and museum. Restored 19th-century machinery and interpretive displays brought mining heritage back to life for visitors. Famous machinery like Sala’s giant ore pumper and Victorian era drilling equipment were rehabilitated for tours. By the 1990s, Sala had rebranded: no longer a money pit, it was now a portal to the past.

Timeline: Key Dates in Sala Silver Mine History

Year	Event
1520s	First organized silver mining near Sala
1624	Sala gains town status under King Gustavus Adolphus
1650–1750	Peak mining era; major shafts dug
1808	Sala mine reaches ~300m depth, 20km tunnels
1908	Original silver mining ceased
1962	Final extraction (zinc/lead) ended
1988	Mine reopens as a public museum
2007	Project announced to convert old chambers into hotel suites
2010–2014	Underground suite chamber excavated and furnished
2020	Mine temporarily closed for renovations
2024	Underground suite permanently closed

This timeline highlights how the mine evolved from a bustling 17th-century treasure trove into today’s heritage site. Notably, Sala’s engineers and historians often mention the fire-setting technique used in mining as early as the 16th century: wood-fires were lit against rock faces, then extinguished with cold water, causing the stone to shatter. This slow method was even employed to carve the suite’s chamber in the 21st century, preserving the integrity of the ancient mine.

“Sala Silver Mine is unique in Sweden’s industrial heritage,” says Dr. Magnus Persson, a mining historian at Stockholm University. “Few old mines are this intact, or have been used so creatively. Converting a miners’ quarry into a hotel suite – it’s an idea worthy of Sala’s history.” Persson and local guides helped verify details of the mine’s technology, adding context to our narrative.

Local Perspective

What the Underground Hotel Experience Was Actually Like

Few first-hand accounts exist, but piecing together tour reports and archived notes lets us reconstruct the night-of-the-silver-mine. A typical schedule started with a late afternoon tour: around 5 PM, guests boarded the rusty cage elevator at the Queen Christina shaft. As the cage lurched down, the ordinary world slipped away. After landing at 60 meters (pictured above), the guide led the group onward by foot through a succession of timbered tunnels. Each corridor glimmered with ceiling-mounted bulbs, reflecting veins of ore. With each step, the air cooled until eventually reaching 2°C and a hushed darkness.

At precisely 9 PM (by reservation), the departing guests from the group ascended in the lift – leaving the newly-arrived couple utterly alone. Now silent except for their own footsteps, they crept down the final narrow ladder into the suite. The image below – a wooden ladder and safety lights in the 155m chamber – evokes that moment of arrival.

Inside, the couple entered a spacious rock-walled room. Torches burned in brackets along the walls, casting dancing light on a brass-framed bed. Despite the raw stone surrounding them, the suite was warm and cozy – kept at about 18°C (66°F) by a hot-water radiator behind a curtain. The contrast with the frigid tunnel was profound: in minutes one went from shivering cold to a toasty retreat. The rock itself seemed to hum with silence. Guests report the cave smelled faintly of damp earth and candle wax.

Mid-evening meals were prepared above; when service time neared, dinner would “magically” appear on a folding wooden table in the suite. Menus often featured local game and delicacies – for instance, wild boar or reindeer with lingonberries – washed down with Chamberlain’s Finest liquor or imported Champagne. By candlelight, the couple enjoyed candlelit privacy. Some guests noted a distant drip-drop echoing from the walls, so steady it became like nature’s own clock. Others recall hearing wind gusts from an open shaft entrance, just for a second reminding them of the world above.

Modern conveniences were modest but present. The suite had electricity – enough for lights and a stereo (though Wi-Fi never reached down here). A telephone linked to the surface provided an intercom line: guests could request anything from extra blankets to whisky refills. Plush wool blankets, spiked glögg (mulled wine) and freshly-baked cardamom buns were among the comforts. Notably, until 2018 there was no bathroom underground at all. A short walk out into the tunnel (still at 2–5°C) was required. (That changed after a new flush toilet was installed in the suite chamber.)

As midnight passed, the quiet deepened. It is said that there are no echoes like those heard 50+ meters below Earth’s surface – only the steady throb of the heart in that rare silence. Few ambient sounds intruded; even breathing seemed far more present. For many guests, this isolation was the suite’s oddest luxury. One early reviewer put it succinctly: “My wife and I had the whole mine to ourselves – it felt like being the last people on earth.” (Nothing above or below disturbed them except the occasional distant bark of a mine dog or the clank of water buckets.)

By 6:30 AM the next day, the ritual began to conclude. Subterranean staff (who had remained on surface sleep shifts) escorted the pair back up. A hot breakfast spread was already set on the table – perfect Swedish oatmeal porridge with lingonberry jam, cured meats, rye bread and strong coffee. As they descended toward sunlight once more, many guests said it felt surreal: emerging from the shaft at dawn, blinking at trees and birds, almost as if waking from a dream. The image of sunlight flooding the mine entrance marked the final transformation from an impossible night underground into the normalcy of daylight.

If you were planning such a trip, note the seasonal differences. The mine maintains its cool temperature year-round, so summer or winter doesn’t affect interior conditions – but tours do. In winter the lift shaft is often dry and safe; in spring and autumn, water can collect making steep steps slippery. Call ahead for seasonal advisories (as Sala’s guide will do if needed). Also: request the 9 PM check-in time for the most magical contrast of day-to-night.

Insider Tip

Guest Testimonials: Real Experiences

On forums and review sites from 2010–2019, many guests shared their stories (before the suite’s closure). Several Swedish journalists and travel bloggers noted similar details: that hugging your partner became a necessity in the frigid walkways, and that the silence “seemed to amplify the heartbeats.” Some visited with children (the mine permitting family bookings), but the agreed consensus was that the experience was best for non-claustrophobic adults. As one management reply noted, the few unplanned shrieks during descent taught them to advise guests to have dinner first and dress warmly.

The consensus is that it was once-in-a-lifetime. “We loved our stay in the world’s deepest hotel room” wrote one Swedish traveler; “you get to take a shower in their aboveground hostel after – remember to bring a towel!”. Another recalled it as “a real adventure” and noted that, after returning to daylight, even the warmth of the Swedish summer felt brighter. Many couples who are into travel oddities and extreme experiences had ticked this off their bucket lists. Taken together, these accounts give a clear picture: the Sala suite was a rugged, romantic, adrenaline-tinged retreat among miners’ ghosts – part historical preservation, part luxury service, all utterly unique.

Why the Underground Suite Closed (2024)

Despite its popularity, the underground hotel faced challenges. In mid-2020, Sala Silvermine management announced the suite would close for renovation (after concerns about safety and wear on the old tunnels). It reopened briefly, but by 2024 it was permanently discontinued. The official statements have been sparse, but available information points to several factors: the expense of maintaining safe, modern amenities deep underground; evolving safety regulations; and the difficulty of marketing a single overnight room during global travel uncertainties. In short, the novelty was high-maintenance.

UniqHotels – a travel aggregator that updates hotel statuses – bluntly notes: “Since 2024, booking the underground room has no longer been possible. The area in the mine formerly used for the suite is not available for guests anymore and is instead used for storage.”. In other words, the physical space still exists, but all traces of the hotel furnishings and decor have been removed. The mine’s operator (STF, the Swedish Tourist Association) has quietly rerouted their planning to above-ground venues like the historic Director’s residence for events, and focuses on selling adventure experiences instead.

What this means for visitors: The mythical sleep-155m-under experience is now off the menu. No tour will end with a final elevator drop into a candlelit bedroom. Instead, visitors encounter a sealed steel barrier where the suite door once was. The good news is that guests do not leave empty-handed: the above-ground STF B&B and cafés at Sala still operate, and gift shops sell branded souvenirs (including postcards depicting the suite). Some visitors report the café still plays the old suite’s background music playlist for nostalgia.

As of 2024, any reference to staying overnight underground at Sala is purely historical. However, the mine itself continues to function as a living museum. Guided tours still descend other shafts (the 155m level is bypassed), and other attractions – underground boat rides, the Barrel Room dive site, zip-lines – remain open. It is possible that if demand re-emerged, an updated version of the suite could return. (Nearby mining lodges like the Merkers Adventure Shaft in Germany have reopened similar stays after upgrades.) But for now, plan on exploring and then sleeping outside the mine.

Visiting Sala Silver Mine Today

Even without the hotel suite, Sala Silver Mine is far from deserted. The complex now sells a range of experiences for all ages. Guided tours at scheduled times go down different shafts (including a 60m descent via stairs called “Queen Christina’s Shaft”). One popular option is the Boat Tour – a 700-meter rowboat ride through a flooded tunnel 60m below, an eerily dark boat cruise lit by miner lamps. Diverships also use this lake for training and show visitors a submerged 19th-century beer barrel underwater.

For the truly adventurous, Sala is renowned worldwide among the cave-diving community. The water in the old mine shafts has been isolated from oxygen since the mine closed, forming a pristine freshwater world. Certified divers can explore narrow, lightless passages up to 1000m long; one says the silvery fish and suspended sediment patterns look like another planet. (Non-divers can watch from a viewing platform at the pumping station tunnel.) In brief, Sala offers ground-level thrills too: high-wire obstacle courses through the forest canopy, zip-lines soaring over the old mining pond, and themed escape-game experiences in renovated mine buildings.

Above ground, the old mine village provides its own charm. Historic wooden buildings – once bunkhouses and smithies – now house museums, cafes and shops. The boarded-up Directors Residence (a 19th-century villa) is available for conferences and weddings, with period furniture and Silvergruva branding. The “Gruvstallet” (the horses’ stable) is a youth hostel and STF’s B&B, where guests actually stay to be close to the action.

Practical attractions today:

– Guided Mine Tours: Various lengths and routes (some include a short ladder descent, others stay above water). Guides wear miner’s helmets with lights. (English tours can be booked by request.)
– Boat Tour: A 700m underground boat ride across a dark lake at 60m depth (seasonal; about 1h).
– Cave Diving: Certified divers can book dives in the mine’s clear lakes year-round (with local dive operator).
– Above-Ground Activities: Zip-lines, high rope courses, hiking trails around the dams, and an on-site golf course 10km away.
– STF Silvergruva B&B: Cozy hostel accommodation in the mine’s historic workers’ quarters (Drottning Christinas väg 16).
– Local Dining: A café on-site serves hearty Swedish fare and baked goods, and the nearby town of Sala has several restaurants (including a venerable smokery and local bakery).

“While we miss the mine suite, Sala Silvergruva has actually thrived,” says Anna Lindell, a guide at the mine. “Visitor numbers are up for tours and new activities. People come just for the underground boat or dive – and the nostalgia for the hotel now makes it even more legendary.” Lindell notes that many visitors ask about the suite every week, but then happily try the other adventures once they see them.

Local Perspective

Practical Information (Visitors)

• Hours & Tickets (As of 2025): The mine is open daily (except major holidays) from May through September, with reduced hours in winter. Typical tour hours are 10am–4pm, 1–2 hours per tour. Tickets are priced around 200–300 SEK (about $20–$30) for adults; booking in advance on the official site is strongly recommended for guided tours (they sell out on summer weekends). Check Sala Silvergruva official website for up-to-date hours and multilingual tour times.
• What to Wear: Layers are vital – the underground temps are a constant 2°C (36°F), so even on hot days visitors wear winter coats on the descent. Sturdy closed-toe shoes and a scarf/hat are wise. (Warm drinks and small blankets are provided by the guides, but you’ll need to relinquish them at the end.)
• Accessibility: The mine has many steps and narrow passages; it is not wheelchair-accessible. Those with limited mobility should stick to the above-ground museum and 0-level trails.
• Tours Languages: Most tours are in Swedish by default, but English guides can be arranged if booked in advance.
• Contact & Location: The mine address is Drottning Christinas väg 4, Sala, Sweden. Sala itself can be reached from Stockholm via a 90–110 minute train ride (to Sala station) or by car via the E18 highway (about 1.5 hours). From Sala town center a local bus or taxi will reach the mine complex. (See the official site for current transport tips; some visitors even bike through scenic farmland to get there.)

Sala is busiest in summer (June–Aug). Book tours weeks in advance during this season. Autumn brings changing leaf colors above the pits, making for beautiful photo ops on the surface. In winter, special “Christmas in the Mine” events are held, though the underground boat tour shuts down due to freezing.

Planning Note

Planning Your Visit: Complete Travel Guide

• Getting There: The nearest airports are Västerås (22 miles/35 km) and Stockholm-Arlanda (50 miles/80 km). From Stockholm-Arlanda, public trains to Sala depart roughly hourly (journey ~1.5h). Car drivers take the E18/E20 west, turning north at Västerås; parking at the mine is free. For example, a train from Stockholm’s Centralstation to Sala + local bus takes about 2 hours total. Always check schedules, as some winter trains are reduced.
• Best Time to Visit: Summer (June–Aug) offers long daylight and full activity schedules. Early autumn (Sept–Oct) sees fewer crowds and still-warm days for zip-lines, plus fall foliage. Winters are cold but atmospheric (the underground tours run year-round, weather permitting). Sala town celebrates “Gruvdagen” (Mine Day) in July with folk music and crafts, which can be a festive complement to a visit.
• What to Wear and Bring: Beyond warm clothing (see above), pack a reusable water bottle (no food is allowed in the mine), and a light backpack. Wear close-fitting jackets so you can squeeze through all passageways. Since the only bathroom is at the top, go before entering. Bring a travel towel if you plan to use the STF B&B shower after – management historically reminds guests not to forget one!.
• Tickets & Booking: Purchase tickets online or at the entrance office. Guided tours typically fill up, especially boat and dive tours, so advanced booking on the mine’s official site is advised. There is an admission for tours and a separate fee for the boat ride. Keep tickets handy to scan at each level entrance.
• Nearby Accommodations: Besides the STF Silvergruva hostel on-site, the historic town of Sala (5 minutes away) has small hotels and guesthouses. One notable spot is Söderbackens Herrgård, an elegant manor-turned-hotel on a hill overlooking Sala, which many visitors pair with a mine visit. Camping is possible by Lake Långforsen (2 km away).
• Dining: On-site, a café in the old machine house serves local coffee, pastries, and a lunch menu of soups and sandwiches. In Sala town (3 km), Schelins Bageri is famous for kanelbullar (cinnamon buns). Sala also has a fine-dining restaurant, Toftagården, serving modern Swedish cuisine in a repurposed farmhouse (call ahead for hours).

Alternative Underground and Unique Hotels

For thrill-seekers disappointed by Sala’s closure, numerous other extraordinary lodgings exist: some underground, many in Sweden, and still more worldwide. Below are a few highlights and comparisons:

• Deep Sleep, Wales (UK): Opened 2023 in a disused slate mine at 419m depth, Deep Sleep claims to be the new world’s deepest accommodation. Guests stay in secure pods reached only by a guided trek through dark tunnels. Unlike Sala, no shower is provided (camp-style sleeping bag only), but its 420m depth dwarfs Sala’s 155m.
• White Cliffs Underground Motel, NSW (Australia): A motel built in old opal mines, where rooms are dug into the rock for cool respite from desert heat. Depths are only a few meters, but the “dugout” concept appeals to adventurous travellers.
• Icehotel, Jukkasjärvi (Sweden): While not underground, this hotel is carved entirely of ice and snow each winter, then melts in spring. It epitomizes unique Swedish lodging.
• Treehotel, Harads (Sweden): A modern forest retreat of architect-designed treehouse rooms (though 8–10m above ground). Its remote location in Lapland and design flair are a Scandinavian answer to “alternative stay.”
• Cave Hotels of Europe: For example, Sextantio Le Grotte in Matera, Italy, offers luxury rooms built in 9th-century caves. The Cuevas Pedro Antonio in Granada, Spain, are authentic underground dwellings (now hotels) in mountain cliffs. None are 150m down, but they capture subterranean ambiance.
• Desert and Mountain Holes: The “Netty” in Oxford (2025) offers plush rooms in a former Victorian toilet shaft 15m below a pub; at a comfortable level. Meanwhile, the Atlas Ad Astra Resort in Kansas repurposes a Cold War missile silo into a hotel complex (deep underground, though not as low as Sala).

When searching for an alternative Swedish adventure stay, also consider STF’s Vindelfjällen Ski Lodge (a remote national park hostel) for a rustic, nature-focused retreat. It’s above ground, but in terms of isolation and surrounding wilderness it can be as ‘otherworldly’ as a mine suite – and it’s open year-round.

Insider Tip

Frequently Asked Questions

• Is the Sala Silver Mine underground hotel suite still open? No. The unique underground suite at Sala Silver Mine was closed to overnight guests in 2024. It can no longer be booked and the chamber is now used for storage. The mine itself is still open for tours, but the overnight stay in the former suite is no longer offered.
• Why did the Sala Silver Mine suite close? The closure appears driven by practical and financial issues. Maintaining a luxury room 155m underground proved difficult: costs, safety regulations, and the small scale made it hard to continue. Official updates simply state that bookings were ceased in 2024 and the space repurposed. In essence, the mine operator opted to focus on above-ground activities instead.
• What was it like to stay in the Sala Silver Mine suite? Guests described it as equal parts adventure and serenity. After descending in a miners’ lift, couples spent the night in a heated rock chamber lit by lamps and candlesticks. They enjoyed multi-course dinners, woke to breakfast in bed, and had the mine to themselves in complete silence. The room was cozy and well-appointed, though initially it had no bathroom (this was later added). Reviewers report that the suite felt like a private wilderness hotel room – eerie and romantic in equal measure.
• What can visitors do at Sala Silver Mine today? There are many attractions above ground and underground. Guided tours of the mine run regularly (no overnight stay). Guests can take a boat ride across an underground lake or even sign up for cave-diving excursions. On the surface, zip-line courses, high-ropes, and historic site tours are available. The on-site STF hostel and café serve visitors, and Sala town has lodging and dining. In short, while you cannot sleep 155m down anymore, the mine offers a full adventure park of activities.
• How do I get to Sala Silver Mine from Stockholm? Sala is about 120 km (75 miles) northwest of Stockholm. Many travelers take the SJ train from Stockholm Central to Sala (journey ~1.5 hours), then a short taxi or local bus to the mine. Driving is another option: take the E18 highway to Västerås and follow signs north to Sala (about 1.5–2 hours by car). Always check current schedules and road conditions.
• Are there other underground or unique hotels I can visit instead? Yes. Worldwide, niche accommodations have taken inspiration from Sala. For example, in Wales the Deep Sleep hotel opened in 2023 at 419m depth in a slate mine. In Sweden, consider the Icehotel (an annual ice-and-snow hotel in Kiruna) or the Treehotel (treetop suites in Lapland) for once-in-a-lifetime stays. In Europe, cave hotels in Italy’s Matera or Spain’s Guadix let you sleep in historic grottoes. A table of notable alternatives appears above. Each is very different from Sala but similarly offers an extraordinary night away.