Nestled in the woods lies this land art project: a hybrid between park, maze and natural monument.

A farm turned upside down.

The world's most active stratovolcano is almost always erupting.

This unassuming retro burger joint was billed as “diner of the future” at the 1939 World's Fair.

This former hydraulic laboratory is now a woodland dotted with old engineering models.

Repurposed space and ultra-modern construction collide to create this geometric wooden spectacle.

This historical Netherlands fortress still bears the marks of its single siege.

Incredible labyrinth of man made caves.

The other side is actually green.

Founded as a refugee camp, now a popular tourist spot.

This overlooked street light once served as a KGB dead letter box.

The broken skateboards that became a poignant memorial to a murdered skater.

A network of concealed passageways lies within a busy London Underground station.

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

Pop culture has helped to keep this iconic British building from being destroyed.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

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

The site of London's first coffee house has been serving refreshments of one kind or another for 360 years.

In this cobwebbed old operating theater, you can practically hear the screams of the unanesthetized patients.

Hear the quietest sound from across the dome.

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

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

A student driver's nightmare.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.