There's no excuse for staying in a bland chain hotel when you can check into a cave, a tipi or a room in the shape of a dog. Here's the quirkiest accommodation you'll find in the USA. Inspired to find somewhere exceptional for your next trip? Our friends at Secret Escapes have some excellent deals on US hotels and vacations.

Perhaps not one for claustrophobics, the luxurious Beckham Creek Cave Lodge is a 6,000 sq ft cave complex in the Ozark Mountains.

It's available to rent out in its entirety, sleeping up to eight in its cave bedrooms.

Set high on the mountainside, the windows look out on to the valley below.

We couldn't have a list of unusual hotels without at least one in Vegas, and Circus Circus is among Sin City's most outlandish places to stay.

As well as circus performances, it has an indoor theme park, the Adventuredome.

Here you'll find the Canyon Blaster, the only indoor double-loop, double-corkscrew roller coaster in the world.

Portland's first (but no longer only) tiny house hotel has six mini homes you can stay in, each individually designed.

Smart design means these compact rooms have all the essentials, including a shower room and kitchenette.

The Amazing Mysterium is the newest addition to Caravan, and despite being the smallest, it can sleep up to four people.

This quirky motel has been run by the same family since it first opened in 1950.

Although it's called the wigwam motel, guests actually sleep in 15 tipis (there is a difference!).

Located along Historic Route 66, the motel also has a collection of classic cars on show.

For a chain hotel, this Crowne Plaza is surprisingly unique.

Located within Indianapolis's old station, it has rooms in old train carriages, still positioned on the tracks.

And you can admire the original architecture in spaces like the ballroom.

You can't miss Dog Bark Park – just look for the giant beagle.

Inside this 12ft-tall canine is the park's only accommodation, a (no surprises here) dog-themed room.

Around the property you'll find wooden sculptures created by the chainsaw artist owners, some of which you can buy in the gift shop.

To stay at what claims to be the world's only truly underwater hotel you have to be a qualified scuba diver, or take a course on arrival.

That's because you actually have to dive 21 feet to get to your room, which is accessed through an opening underneath.

Yes, as in the actual Queen Mary – the ship that once plied the Atlantic between the UK and the USA.

Retired from service as a cruise liner in 1967, she now lives on the Pacific, where visitors to Long Beach can spend the night on board.

Cabins have been restored to how they were in their heyday, with art deco features and 1930s artwork, while guided tours will take you to the ship's bridge and engine room.

Getaway's collection of wooden box-like cabins are all either within two hours of New York City or Boston.

Inside they're minimalist but functional.

Guests are only told the exact location once they've made a reservation.

Right next to Rocky Mountains National Park, the 100-year-old Baldpate Inn looks fairly unremarkable from the outside.

Once you get to reception, however, you'll find the largest collection of keys in the world – around 20,000 of them, many of which hang from the ceiling.

The hotel is based on the inn from the 1913 mystery novel Seven Keys to Baldpate.

Just outside the gates to the Legoland park, this is the ultimate hotel for Lego-lovers.

Around the hotel are more than 2,000 models, made using more than two million Lego bricks.

Rooms are themed and each has a treasure hunt for kids to complete.

Another place where you can sleep in an old train carriage, Featherbed Railroad sits right on the shore of Clear Lake.

The nine vintage caboose cars are dotted around the park-like property, with breakfast served in – where else? – Central Station.

Each room is themed, from the biker-friendly Easy Rider to the Art Deco-inspired Orient Express (pictured).

Don't want to travel all the way to north Africa? Experience the Vegas take on the ancient Egyptians instead.

At the Luxor, guests can check into rooms in the central pyramid and take a boat ride along the 'Nile' to different parts of the hotel.

There's also a replica sphinx, and by night, a beam of light (said to be the world's strongest) shoots out of the pyramid.

The brave can stay over on an abandoned US Coast Guard light station, 34 miles off the coast of North Carolina.

The tower has eight guest rooms, and even a helipad for those arriving by chopper.

With no other structure or land in sight, you can spend your time diving, fishing and even playing golf.

Arrive by night and you'll get an immediate inkling there's something different about The Roxbury.

The themed rooms include the Wizard of Oz-inspired Wizard's Emeralds, complete with its very own Yellow Brick Road.

Alternatively, try Maryann's Coconut Cream Pie, where everything from the pillows to the ceiling makes you feel like you're inside a giant dessert.

Just outside Capitol Reef National Park you'll find a collection of 19th century-style wagons.

Each sleeps up to six people, and is considerably more luxurious than it would have been in the 1800s.

In the daytime you're surrounded by red rock, and after dark there's great stargazing.

This 113-acre estate in Connecticut has 18 themed cottages, including a treehouse.

Another of the cottages comes with its very own helicopter inside, and while you can't sleep in the chopper itself, you can admire it from the bed. Want to book somewhere amazing for your next trip? Check out Secret Escapes' fabulous hotel deals.