Most of us are just looking for a place to rest our heads when we stay at a hotel. But for the more curious and adventurous, there is an eclectic array of bizarre hotels to check out on your travels.

There’s a hotel in South Dakota that serves as an homage to Tolkien’s Lord of the Rings, with circular windows, doors and even a Sauron Mask. In New Zealand there’s a fairy tale-esque hotel that is shaped like an actual boot. In Austria, there’s an actual sewage pipe that serves as a hotel where you can rest your head. In Boston, a 19^th century jail is now a trendy hotel with clever winks to its past as a prison. There is a partially submerged underwater inn where visitors can sleep in Sweden. An actual fort in Portsmouth now serves as a luxury hotel for guests. For the dare devils out there, a hotel in Iceland has you sleeping on a dormant volcano amidst lava fields. A hotel nicknamed Crazy House in Vietnam features animal and nature themes. Guests can sleep with the sharks in underground accommodations in Paris. There’s even a hotel made out of salt in Bolivia.

Keep reading for 15 of the world’s most bizarre hotels.

15. Hobbit House

If you’re a Lord of the Rings / Hobbit fan, you’ll love Hobbit House. Hobbit House is inspired by Tolkien’s works. Located in the Black Hills of South Dakota, you’ll find a suite 16 feet high. It has circular windows and doors, a Sauron mask, Hobbit slippers, and there’s even a gauntlet that holds — what else — the infamous One Ring. Even the interior consists of Lord of the Rings-style decorations. You have to stay a minimum of three nights if you choose to stay in the treehouse, which is available for $639 a night — but would you really want to stay for less time than that?

14. The Boot Bed’n’Breakfast

So this bed and breakfast is exactly what it sounds like… a guest house in the shape of an enormous boot. Inside, you’ll find custom made curved ceilings and walls. In the lounge, you’ll find an open fire and a couch. There’s a place to make tea and coffee as well as mini bar in the kitchenette. The spiral staircase leads to a bedroom complete with a balcony that overlooks the courtyard and pond. It’s perfect for a cozy stay solo or with a partner — you can have breakfast delivered right to your room if you choose.

13. Sewage Pipe Pods

If you’ve ever been curious about what it’s like to sleep in a sewage pipe, well you’re in luck. In Ottensheim, Austria, you’ll find the Das Park Hotel, which was made out of sewage pipe sections, refurbished to serve as shelter. The Das Park Hotel is the brainchild of Austrian architect Andreas Strauss. You can pay what you want and stay in a room with the basics — bed, power outlet, blankets, lamp, and small storage space. Now the irony is that there is no bathroom here due to the lack of an actual sewage system — you’d have to use a nearby public bathroom.

12. Liberty Hotel

Want to stay in a hotel that used to be a jail? Well, Boston’s Liberty Hotel is just that. Back in 1972, this hotel was once the Charles Street Jail, a decrepit space. The Charles Street Jail had been completed in 1852 by the architect Gridley James Fox Bryant and Rev. Louis Dwight. It became the cleaned up and hip Liberty Hotel, located in Beacon Hill. Here you’ll find exposed brick walls, arched glass windows, dazzling chandeliers, and a rooftop cupola. As a wink to its past as a jail, there are jail bars in bar lounges, and the restaurant is called The Clink.

11. Utter Inn

In Lake Malaren, Sweden, you’ll find the Utter Inn, which is actually an art project that serves as a hotel by Mikael Genberg. The little red house is on the water — in the middle of the lake, in fact — and guests who enter will find a bedroom that has been submerged along with panoramic windows showing fish swimming by. The part that is above water has a kitchenette, dining area and outdoor terrace. You have to use a ladder to get to the submerged bedroom — located 3 meters underwater. The hotel staff brings guests to the Inn by boat.

10. No Man’s Fort

No Man’s Fort is a fort that was built in between 1867 and 1880 to guard against an attack from Napoleon III. It is the largest of the three man made forts of the Solent Forts. Well, now it is a hotel, and a luxurious one at that, complete with a lighthouse penthouse suite, 22 bedrooms, a hot tub, and even a nightclub; so there is plenty to do and explore in a hotel that was once a military fort. The unique architecture is worth the price of a visit alone — how many people can say that they’ve spent the night in an actual Victorian-era fort?

9. ION Luxury Adventure Hotel

The name of the ION Luxury Adventure Hotel is no accident — this hotel is in the volcanic belt. It is surrounded by lava fields and mountains — in fact, it juts out from a dormant volcano. This is definitely a hotel for the adventurous. You’ll find it in Iceland, outside of Reykjavík. It is an ideal place for viewing the Northern Lights, fly fishing, or even making a journey across one of the ancient glaciers. It is also near Thingvellir National Park, which is a UNESCO World Heritage Site. The hotel plays up its natural backdrop — there is a bar called the Northern Lights bar and a spa called the Lava Spa.

8. Palacio de Sal

In southwest Bolivia you’ll find the Palacio de Sal, translated as Salt Palace. Its name comes from the fact that it is completely made out of salt — even the furniture, believe it or not. This isn’t for fad reasons — building materials are scarce in the area. It is located on the salt flats of Uyuni. These salt flats are the largest in the world. The hotel consists of a bar and 16 rooms with the basics — electricity, private bathrooms and heating. The first iteration of the hotel was built from 1993 to 1995, quickly becoming a tourist destination.

7. Hang Nga Guesthouse

This hotel is also known as Crazy House — for good reason. It looks jumbled and out of sorts with its decidedly Gaudi-like construction, designed and constructed by Dang Viet Nga. The kooky design is supposed to be like that — it is meant to look like a tree. It incorporates elements that mimic forms in nature like animals, spider webs, caves and mushrooms, likely to support its fairy tale house theme. The architecture consists of complex and non-rectilinear shapes, resembling a work of art more than a hotel. So if you’re in an adventurous mood and going to Vietnam — check out this hotel.

6. Underwater Shark Tank

Another hotel that submerges guests underwater is a hotel / Airbnb in Paris near the Eiffel Tower. This is actually a collaboration between the French firm Ubi Bene and Airbnb. In the underwater suite, guests sleep inside a glass capsule 33 feet deep. The 3 million liter tank that surrounds the suite is filled with 35 sharks. The chamber is see through, so the guests who are especially brave can see the sharks as they swim by. There is nothing but a wall of glass separating the guests from the sharks. If you’re the adventurous type and have ever wanted to sleep near sharks — this is your chance.

5. Robot Hotel

For a taste of the futuristic, check out Japan’s Henn-na Hotel — or Robot Hotel. Rather than use a boring old human staff, the hotel uses humanoids and robots who speak both Japanese and English. This is the world’s first hotel that is staffed by robots. The work as receptionists, the concierge, porters, even in-room robot assistants. The in-room assistants help out with such things as room temperatures, check ins, lights, even weather forecasts. Note — there is an actual human staff on hand just in case there is a malfunction with one of the bots. In any case — the future is here at the Robot Hotel.

4. Hotel CasAnus

With a giggle inducing title, Hotel CasAnus is exactly what it sounds like… a giant intestine. Located in Antwerp, Belgium, in the Verbeke Foundation Art Park, the sculpture / hotel was created by Joep Van Lieshout. Once you enter the.. Er… intestine, you’ll find an electric heater, double bed, and shower with hot water. The interior is also… curved as to be anatomically correct. On the exterior, you’ll find a sphincter (yep) and realistic veins. It’s painted the same red color of organs that have been exposed. Despite how garish it may seem, visitors come here to enjoy nights with views of the night sky and black swans.

3. Kakslauttanen Hotel

Want to spend the night in an igloo? Well, head over to Saariselkä, Finland, where you’ll find Hotel Kaklauttanen. The hotel consists of glass igloos, complete with views of the stars in the night sky and the Northern Lights, visible during the season from August to April. It’s located off the highway leading to the Arctic Sea, and it is surrounded by nature — forest and sky. It’s not far from the Urho Kekkonen National Park. The rooms themselves have saunas and fireplaces, select ones have free standing tups and kitchens. There aren’t televisions — but would you really need one with the spectacular views these rooms provide?

2. Giraffe Manor

Back in the 1930s, European visitors first came to Nairobi, Kenya for safaris. Giraffe Manor is a throwback to such a time — and the title is no joke; actually giraffes live here and even poke their enormously long necks through the windows. Designed to look like a Scottish hunting lodge, it was built in 1930 by Sir David Duncan on 150 acres of land in the southern area of Nairobi. It fell into disrepair in the 60s before being purchased by Betty Leslie Melville in the 70s. Now the manor is a place for visitors to enjoy the sights — and the friendly giraffe visitors.

1. Upside Down Hotel

If you don’t have the tendency to get dizzy, the Upside Down Hotel in Berlin is a hotel to check out. Officially called the Propeller Island City Lodge, it is an odditorium of sorts. Each room has a strange theme — a coffin suite in which the beds are coffins, a levitating bed suite, a green leather suite, a mirrored room, and a weird upside down suite. In the upside down suite, furnishings actually hang from the ceiling. Guests sleep in compartments on the floor. So if you are a fan of the bizarre, the Propeller Island City Lodge is definitely an ideal place to stay.