A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

An alchemist's "magic door" stands in the middle of a Roman park.

Rebuilt remains of a temple to Roman god Mithras.

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

Eighty million natural history specimens call this gargantuan museum home.

Ruins of a German Castle on top of a towering stone pillar.

A Jenga-style cylindrical tower of books that appears to go on forever.

The magical, mossy forest that inspired Princess Mononoke.

An unusual round church in London with a Templar past.

Museum preserving torture methods from the past.

Rising from the sea like a stone monster.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

An ancient capital city that dates back 3,000 years old and harbors many surprises.

The most visited, and possibly most controversial, museum in Germany.

A submerged archeological park still holds the wonders of a Roman Sodom.

Home to items never before seen by the public.

The site of the climactic scene from the classic horror film is now a historic landmark.

The first declared National Monument in the United States.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

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

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

This massive library holds what was once the largest book collection in the world.