No Man's Fort, Solent, Portsmouth

No Man’s Fort – a Victorian-era fort which was originally built between 1867 and 1880 to protect Portsmouth from an attack from Napoleon III – has been turned into a luxury hotel, with 22 bedrooms, a lighthouse penthouse suite, nightclub, hot tub and laser quest arena.

Palacio de Sal, Uyuni, Bolivia

The Palacio de Sal – ‘Salt Palace’ – on the salt flats of Uyuni, is completely constructed from salt, including most of the furniture. There’s an impressive lobby, bar and 16 rooms with private bathrooms, central heating and electricity.

Hotel Marqués De Riscal, Elciego, Spain

The Marqués de Riscal is architect Frank Gehry's first and only hotel project, located in Elciego, in the heart of Spain’s Rioja wine-growing region. Similarly to his other projects, such as the Guggenheim in Bilbao and the new Fondation Louis Vuitton in Paris, the structure is avant-garde in its approach, using huge titanium ribbons which stand out from the surrounding vineyard. The restaurant and bar are first-class, and there’s also a separate spa wing.

Crane Hotel, Harlingen, The Netherlands

Guests will forgive this hotel's less-than-glamorous dockside location once they get inside the 150ft-high room: you can rotate the room 360 degrees to enjoy panoramic views of the Wadden Sea.

Capsulevalue Kanda, Tokyo, Japan

Originating in Osaka, the capsule hotel is a popular concept in Japan. Stacked side by side and on top of one another to maximise on space, you can expect to pay around £30 per night. The idea has even travelled over to Europe – Helsinki airport will introduce their own sleeping pods.

Cedar Creek Treehouse, Ashford, Washington, USA

Constructed between the early 1980s and 2000s in the Pinchot National Forest, the collection of treehouses at Cedar Creek are cinematic. The treehouses look, quite literally, like a house has been placed up a tree. The observatory offers views of the Mount Rainer.

Jumbo Stay, Stockholm Arlanda Airport, Sweden

This former Jumbo Jet, dating from around 1976, has been converted to provide overnight accommodation. Choose between an en-suite room, budget dormitory or twin rooms. The best room is a luxury cockpit suite complete with panoramic view – you might even catch some planes landing at Stockholm Arlanda next door.

The Hobbit Motel, Woodlyn Park, Waitomo, New Zealand

Put aside your preconceptions of the soulless motel – these Lord of The Rings-inspired rooms invoke homely charms suitable for the most discerning of hobbits. It’s two hours from Auckland and just two minutes from the Waitomo Caves.

The Manta Resort, Pemba Island, Tanzania

If you can’t wait for Poseidon to open, then The Manta Resort in Tanzania has its very own Underwater Room. The floating structure has three levels, including a roof which is perfect for launching off into the sea. Downstairs, is the below-sea level bedroom, where you’ll see friendly trumpet and bat fish, Spanish dancers, squid and octopus.

The Boot Bed’n’Breakfast, Tasman, New Zealand

The giant boot guesthouse, created by Steve and his partner Judy in 2001, is wonderfully eccentric. The curved walls and ceilings means everything has been custom made.

Utter Inn, Lake Mälaren, Sweden

Utter Inn (Otter Inn in English), is an art project by Mikael Genberg located in the Lake Malaren, near Västerås in Sweden. On entering the little red house on the water, guests will discover a submerged bedroom, with panoramic windows.