Subterranean Sites

This centuries-old mine remained hidden beneath a hotel bar until 2013.

These underground shelters dug by the Japanese during World War II later helped Timor-Leste achieve its independence.

The only subterranean ping pong table in Atlanta.

One of Mother Nature’s geological gems, home to many prehistoric fossils.

A sixth-century Byzantine cistern hidden below a modern carpet store.

These crevices cut into the mountains collect the island’s main source of precious freshwater.

A Roman spa buried deep beneath the City of London.

This secluded walking trail is a hidden gem of a Pittsburgh park.

This small museum tucked within a subway station holds pieces from Madrid's past.

Its dark depths conceal millions of rare, delicate crystal formations.

This fascinating cave is packed with prehistoric rock art and Stone Age tools.

This army of concretions is an unexplained geological phenomenon unlike anything else in the world.

A cozy bookstore is tucked within an old gold mine shaft beneath the cafe and ice cream shop.

Built on a medieval synagogue, this church has a burial crypt, tunnel system, and Jewish ritual bath hiding deep underneath.

An enchanting tunnel of cypress trees leads to an old morse code station still used today.

This fantastic cave remained unexplored until 1948 when three schoolboys discovered a hidden entrance.