Knoxville’s architectural icon was the symbol of the 1982 World’s Fair, even catching the googly eye of Bart Simpson.

This former maximum-security prison is creepy, sobering, and supposedly haunted.

John Hendrix predicted the creation of the "Secret City" built as part of the Manhattan Project.

This hotel was used during the Manhattan Project to house official visitors.

The secret city built by the Manhattan Project.

One of the Cemestos prefab homes built to secretly house thousands of Manhattan Project workers.

On a winding Vienna side street, one museum has turned their windows into a monument to history’s peace-minded heroes.

Handsomely crafted representations of our round planet.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.

The beautiful baroque library of the Hapsburg empire.

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

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.

A fake Transylvanian castle houses a cathedral of antlers.

This statue of a falling man commemorates a teenage martyr of the Hungarian Revolution.

A random tree outside a Budapest hotel has become a DIY shrine to the late singer.

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

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.

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

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

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

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

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

This 19th century cyclorama acts like an analogue time machine to a different era.

Terrifically morbid cemetary and site of famous Paracelsus' grave.