A monumental toilet that is also host to rare plants.

Above the door of a house, a plaque claims to commemorate the future living place of the inventor of time travel.

A neighborhood church's unusual abstract stained glass was the final project of avant-garde artist Jean Cocteau.

The Belgian royal family's private depot now stands abandoned and forgotten alongside the tracks.

Old batteries and frog skeletons reside in this lakeside monument to Alessandro Volta.

A socialist building dedicated to teachers showcases one of the largest Soviet mosaics in the world.

This statue dedicated to the story of a Flemish boy and his dog was relatively obscure in Belgium, but a cult sensation in Japan.

This narrow path was cut right into a French mountainside to feed the country's early naval expansion.

A beautiful lighthouse with as many steps as days in the year, as many windows as weeks, and as many levels as months.

The Lone Star plaque hangs in a bombed-out bunker in Normandy to honor a Texan colonel's heroic actions on D-Day.

A massive, gleaming sea turtle with a rider atop its shell looks out over the horizon.

This ancient theater was once the home of fierce gladiatorial battles.

At the very tippity-top of Europe is a cliff from which you can view the midnight sun.

World's strongest whirlpool.

This still-celebrated home was a radical architectural experiment in 3D De Stijl.

A collection of weird and wonderful art fills a former houseplant nursery.

Rare wooden escalators lead deep down into an otherwise staggeringly monotonous tiled tunnel.

Most prolific publishing house in the 1600s open to the public.

The patron of this extravagant Art Nouveau confection insisted that nothing less than a boat should project from its facade.

As the highest point in the Mid-Atlantic range this stratovolcano offers spectacular views.

This abandoned five-star hotel is now a five-star urban exploration destination.

The central mosque of this Mali town is entirely built from mud.

These homes carved into the mountains seem to defy the laws of nature.

One of Western Africa's oldest mosques, this Timbuktu icon has stood for nearly 700 years.