Subterranean

This series of underground chambers contains Europe's largest subterranean lake that is slowly drained each day.

The labyrinthine storm tunnels beneath the city of Melbourne are ruled by a band of urban explorers.

The longest navigable underground river in the United States is home to countless blind and albino animals.

This former limestone quarry is now a subterranean wonderland of grand stonework.

This eccentric cave dwelling is bizarre even by the standards of a subterranean town.

One of the most remarkable caves in all of Iceland was created by a once raging river of lava.

This submersible road connecting a French island to the mainland is lined with safety towers for when the tide strands travelers.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

Decommissioned NYC subway cars are dumped into the ocean to create this underwater wildlife habitat.

An underground city of ancient quarry tunnels hid thousands of Allied soldiers in WWI.

Museum design and public transportation meet in this unique Russian train car.