This natural French spring has been turned into a magical grotto by Roman and medieval constructions.

This massive subterranean fissure is known as the "underground Grand Canyon."

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

This small town in the Netherlands has no roads but instead, miles of canals and over 100 bridges.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

A huge wooden clock that is so beautiful its creator was forcibly blinded.

Countless stories attempt to explain Poland's mysterious J-shaped trees.

London's smallest police station is barely the size of a phone booth.

The signs of a long buried road can still be found hidden beneath a London sewer grate.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.