A cave in Bashkortostan with a single chamber holding ice columns up to eleven metres tall, grown over centuries. The temperature stays below freezing all year: cold air flows in during winter and cannot get out. Bashkir tradition places a guardian spirit here, to whom offerings were left at the mouth. In the 2010s visitor numbers damaged some of the columns and the cave was closed to open access.

Read next

Ha Long Bay

Fifteen hundred limestone islands in the Gulf of Tonkin. The name means descending dragon: gods sent dragons to defend the Vietnamese against invaders, tradition holds, and they spat out pearls and jade that became the islands. A separate strand is sailors' accounts of a sea creature that French colonial officers reported in the bay in the 1890s.