Elaborate series of tunnels where traces of mass suicide are still visible.

The seat of the lost Ryukyu Kingdom has survived numerous fires and wars over the centuries.

The smaller of the three towers of San Marino is a former prison inaccessible from the ground level.

High in the clouds of San Marino sits an ancient tower with some curious prisoner graffiti.

A surreal statue honoring Prague's favorite literary son.

The slender brass strip in Prague's Old Town Square was used to tell time from 1652 to 1918.

This spooky statue sits outside a famous Prague theater.

The first museum in the world devoted to sexual gadgetry.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

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

This easily overlooked memorial immortalizes the scars from the 1956 Hungarian Revolution.

This building has survived for more than a century and remains virtually untouched.

A statue in Budapest's Liberty Square honors the former U.S. president's efforts to end the Cold War.

An underground city of salt.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

Inside this Krakow church, an explosion of psychedelic color.

A statue commemorating a Polish dog who took his role as man's best friend very seriously.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

This colorful and quirky set of pegasus sculptures celebrate the works of poet Zbigniew Herbert.

This biographical museum honors the groundbreaking scientist at her birthplace in Warsaw.

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

Catch a scenic view of Warsaw's Old Town from the top of a centuries-old dumping ground.