The abandoned "Red Star Train Graveyard" is the final rusting place for precious artifacts of train history.

Hungarian Jews were ghettoized during the Second World War, but little remains of the original wall that closed the Jewish people off from the rest of the city.

The holes in this wall provide a glimpse into Jewish life in Budapest, both past and present.

On Gellért Hill, this statue depicts the tragic tale of lovers divided by the Danube.

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

Budapest's Communist-era statues, banished to the suburbs.

Tucked away near more famous landmarks lies a statue meant to symbolize the confluence and continuing development of human culture.

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

Once the home of a hermetic monk, this cave now houses a small church.

The most famous location in China was home to whole dynasties worth of imperial rulers.

One of seven Jewish catacombs in Rome and one of only two open to the public.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

Abandoned railway line circling the city of Paris.

This odd California folly seems like it was almost designed to accumulate urban legends.

A World War II officers' club features Old West murals painted by German POWs.

A little stop along the Texas highway where Rock Hudson, Elizabeth Taylor, and James Dean stayed while shooting the 1955 film "Giant."

With print dying, this local paper keeps the lights on by doubling as a stunning cafe and cocktail bar.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

The world's oldest and largest museum of mass transit vehicles.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

An ancient octagonal weather station named for the eight Greek gods of wind.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

This legendary city has been a tourist attraction for centuries.

The ruins of an abandoned medieval city where the last Byzantine emperor was crowned.