Part of an abandoned19th-century fortress hides in plain sight inside a modern office building.

The recurring nature of this geographic feature might make it unique in the world.

This mysterious, medieval cathedral remains unbuilt but fiercely protected.

The fences outside some of South London's estates are made from recycled World War II stretchers.

This fairytale medieval church in Poland originally spent centuries in Norway.

After it was swallowed by a Georgian mansion, this medieval castle remained forgotten for centuries.

The exterior of this home was used for the hit television show, The Brady Bunch.

The illuminating collection of L.A. street lights is run by the city and only opens one day per month.

This pub can leave even the sober feeling slightly unsteady.

The oldest of the three remaining bridges in England with buildings on top of them.

This unusual elevator doesn’t stop or slow down.

This supermarket offers shoppers a window into the past alongside their groceries.

This museum is dedicated to the most famous Irish writers in history.

Magical-looking cottages that inspired one of the most famous animated films ever.

Legend says this demonic carving inside a medieval cathedral was one of Satan's minions.

A replica of the home of a famous fictional troll family.

The final resting place of a space program monolith.

The entrance to this Frankfurt subway station looks like an old tram car crashed into the concrete sidewalk.

The 20th-century chapel’s intricate woodwork includes amazing details, most notably angels playing bagpipes.

This retro underwater observation tower would make the perfect lair for a sea-loving villain.

These quaint cottages feature built-in signaling devices for fishermen.

This copper-coated, multi-arched dome is surrounded by a moat and lights up at night.

A tiny replica of the iconic London landmark hides on the side of the steel structure.

An unlikely beach paradise of giant sand dunes lies between two lakes just a few minutes from Michigan's cherry country.