This colossal war machine is now a living museum dedicated to underwater warfare.

These ruins of Francis Bacon's once-magnificent manor are hidden in the English countryside.

The UK's oldest theme park slowly slips away.

A well-studied colony of endangered bats roosts in this abandoned Victorian Gothic mansion.

This hidden natural fountain issues forth a steady supply of supposedly healing water that tastes like rotten eggs.

This once-majestic, now-abandoned Victorian castle has seen better days.

An impressive home made of stone, carved more than a century ago.

Fantastically decorated underground chambers built in the 1760s.

This Roman quarry once held secret masses and smuggler's contraband and is now home to rare species of bats.

One of the largest mechanical models of the solar system in the world.

This Norman castle has been the scene of assassination plots, religious persecution, and Nazi conspiracies throughout its long history.

Where Agatha Christie mysteriously disappeared in 1926.

An unexpectedly extraterrestrial room in a former Victorian resort club.

A rotting air force base is now home to rare birds and scarce plants.

This bewitching Babylonian goddess haunts a hallway of the British Museum.

These remarkable cascades are the jewels of Upper Tees.

The crumbling remains of a once-grand building.

Once a state-of-the-art tuberculosis treatment spa, these ruins are now ruled by paintball players.

An abandoned asylum where patients have been forgotten but their possessions remain.

A crumbling cathedral condemned by an earthquake.

This group of small islands on Lake Nicaragua formed after an eruption of the Mombacho volcano.

A lavish Victorian mansion wound up inheriting a gruesome reputation that would be its demise.

The ruins of a once-grand mansion in Northern Ireland are now thought to be haunted.

After mysteriously refusing to surrender at the end of World War II this sunken submarine was only salvaged in a search for Nazi gold.