A sulfuric martian landscape that looks far better than it smells.

This volcanic cave lake is essentially hard proof that Iceland is the most magical place on Earth.

Rising from the sea like a stone monster.

The mouldering remains of a disgraced British children's icon are hidden in the brush of a public park.

A rocky sea serpent hides caves, blowholes, and a spectacular natural bridge.

From toys to kettles to scientific instruments, this German museum celebrates the beauty of 20th century design.

The music is over at the Ballhaus Riviera Ballroom, but the ballroom remains in haunting disrepair.

A collection of abandoned typographic signs from Berlin and beyond.

A surreal museum of extraordinary industrial objects.

This beautiful Victorian ironwork masterpiece was built to keep London from smelling like poop.

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

London's largest outsider art museum.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

Following the trail of an old metro line, this scenic path is haunted by a creepy spriggan statue.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

The final resting place to 300 Victorian-era pets hides inside the city park.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

The world's first underground farm is in a World War II bomb shelter beneath the streets of London.

This collection of illusory paraphernalia has been culled from the history of London's premier magician's club.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.

Hidden beneath the streets of London is a secret subway that only carried mail.

The largest of London's subterranean rivers and once a mad, bad center of London life.

An unusual round church in London with a Templar past.

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