Les Hautes Roches, France
At this former monastery turned upmarket retreat on the banks of the Loire, 12 of the 15 lavish rooms are set in caves. However, even if you get one of the three "ordinary" rooms, you don't have to go without the troglodyte experience altogether, since the hotel's bar is also set into the rock. When you want to come up for air, this Relais & Châteaux property also features a sunny terrace, pool and restaurant.
Les Hautes Roches, 86 Quai de la Loire, Rochecorbon, France (00 33 2 47 52 88 88; www.leshautesroches.com). Doubles start at €135 (£93), room only.
The Caves, Jamaica
Definitely the world's grooviest cave hotel, The Caves belongs to Island Records founder Chris Blackwell's portfolio of Caribbean properties. Brightly coloured bohemian decor, a great, all-day, food and drinks list and the most chilled-out atmosphere this side of Alaska are all part of the package. While the guest cottages are all above ground, the hotel is built around a cave-peppered outcrop, dropping directly into the sea. Cool off by swimming in and out of the caves below. Otherwise book in for a massage in the Aveda spa or grab a candlelit table at the hotel's cave restaurant for a dinner to remember.
The Caves, Lighthouse Road, Negril, Jamaica (00 800 688 76781; www.islandoutpost.com). Cottages start at $515 (£286), all-inclusive.
Cappadocia Cave Suites, Turkey
The rooms at this romantic cave hotel are dubbed "fairy chimneys", which isn't stretching the imagination too much. From churches to houses, so many of the buildings in this historic region of Turkey are set into the rock - some so deep that whole cities have developed underground - that the landscape looks completely otherworldly. If you want to try Flintstone living for yourself, Cappadocia Cave Suites is a former hay barn, restored in the 1990s and now serving as a boutique hotel, with 18 atmospheric rooms.
Cappadocia Cave Suites, Gafferli Mah Unlu Sokak 19, Goreme, Turkey (00 90 384 271 2800; www.cappadociacavesuites.com). Doubles start at $150 (£86), including breakfast.
Set in the picturesque village of Oia on the island of Santorini, Alexander's has taken the idea of the traditional cave house and given it a modern twist. The architecture is still reassuringly Cycladic in style, however, (white-washed walls and domed roofs) and the décor features a mix of antique wooden furniture. There's no forgetting where you are when you step outside. From the hotel's terrace the view spins out over sugarcube houses clinging to the rock and the sun setting over the sea.
Alexander's, Santorini, Greece (00 30 228 607 1818; www.alexandershotel.com). Cave houses start at €85 (£47), including breakfast.
Desert Cave Hotel, Australia
Not so much a hotel as the world's most luxurious mine shaft, the Desert Cave opened in Coober Pedy in 1988, making excellent use of the underground climate. That isn't as radical as it sounds - the local opal miners had been living below ground for years, gladly escaping the outback heat. Today's guests don't have to rough it, though. The hotel's 50 suites all have TV and internet and, although a little dated now, were cleverly designed to reflect the landscape. If you think you might get cabin fever, the hotel also has rooms above ground.
Desert Cave Hotel, Coober Pedy, South Australia (00 61 886 725 688; www.desertcave.com.au). Doubles start at AUS$192 (£81), room only.