Cube-shaped hotels have spread out from Spain to Australia and lots of places in between. Among the top 10 examples noted by travel website Trivago.com.au were:
Treehotel Harads, Sweden: This is tree-house living, but not as you know it. Take your pick from the UFO cube, the Mirrorcube, or the Bird's Nest, all suspended from the Nordic pines with wonderful river views.
Sleepbox Hotel Tverskaya, Russia: Moscow's first capsule hotel has 60 affordable sound-proofed rooms with TV, and a wall of iPads in the lobby.
Visitors to Spain are spoilt for choice. Those with a hermetic bent might like the Consolacion Aragon, a modernistic gathering of 10 cubes built around a 14th-century hermitage and 17th-century church; or recline in the bowl-shaped bathtub on your cube patio at Aire de Bardenas, Navarre. The tub has views over the 100,000-acre semi-arid The Bardenas Reales National Park.
Australia is not to be outdone with 15 tents at Longitude 131 in Uluru-Kata Tjuta National Park.