This communist behemoth is the heaviest building in the world and a legacy of a brutal regime.

This once-derelict building is now one of the most beautiful bookstores in the world.

The bust of Romania’s most notorious ruler, Vlad Dracula aka "Vlad the Impaler," keeps watch over the ruins of his medieval court.

The European towns of Brașov and Râșnov each have proud signs reminiscent of the Hollywood sign.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

This stone memorial pays tribute to a massive shipwreck which was sadly overshadowed by the death of John Wilkes Booth.

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.