Ice Hotel is, as you might guess, a hotel made of ice. Several room options are available, from “cold room” options that include sleeping on actual blocks of ice (brr!) or reindeer skins to the “warm room”
Skye Lighthouse is now a hotel
Some prefer the sound of crashing waves and beach access. In that case check into the Skye Lighthouse, in Scotland.
Tree House Lodge in Costa Rica
Weird but also wonderful are the Cappadocia Cave Suites in Turkey, carved during Hittite, Byzantine and Roman days, but now used as lodging.
White Cliffs in New South Wales will put you up in an underground hotel carved out as opal mines