"Stairs of the Turks", a chalky white cliff eroded conveniently into stairs, allowing for easy pillaging.

Italian cave with exceptional acoustics and an unsavory history.

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

Breathtaking and huge 430 year old maps of Italy.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

The topiary maze at the Habsburg hunting lodge.

This one-time health resort was used by aristocrats around the world.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

The world's most important buildings shrunk to a tiny size.

This small, easily-overlooked sculpture recalls the first time Graz saw a live elephant.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

A triumphant marble and bronze fountain depicting a 15th-century Hungarian king and his hunting party.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

An abstract monument to a symphonic composer.

A subterranean house of worship carved right out of the bedrock.

The mile-long pier stretches from a ruined fortress out into the Baltic.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

This ornate church has survived Nazi and Soviet occupation, including a short stint as a Soviet-era gymnasium and cinema.

Guests become prisoners on a visit to Latvian prison.

These crumbling Latvian forts make for some haunting seaside ruins.

This dizzying tower was built to better broadcast the 1980 Moscow Olympics.

The widest waterfall in Europe is a natural wonder and one of the only places where fish are caught in the air.

The Guardian of Tallinn.