The remains of a sunken military ship wreck visible through clear water.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

A museum, walk-through diorama, and library nestled under one castle-like roof.

A once grand hotel now sits eerily abandoned in the Catalan countryside outside Barcelona.

A mouldering Colombian bull ring stands as a reminder of the country's complicated relationship with a brutal sport.

The religious shrine that Pablo Escobar's men would allegedly visit before completing a mission.

One of the world's oldest working clocks is curiously missing the Zodiac sign of Libra.

A slightly creepy gallery of plaster cast models in the same museum as Michelangelo's David.

142 ceramic steps become a mosaic once a year.

A dismembered holy head stares out from her beautiful reliquary at the St. Dominic Basilica.

Colorful concentric circles honor a small Croatian town's supposed spot at the nucleus of it all.

The Renaissance-era courthouse is a relic from the fortified town's centuries of Venetian rule.

An ethereal glowing blue ocean cave in Croatia.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

The fairy tale castle of the "fairy-tale king."

This abandoned coliseum was intended to be a grand Nazi rallying ground before it was halted at the end of the war.

The world's oldest rose is so tough it survived being bombed in World War II.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.

A 12th-century fortress containing some of Berlin's oldest buildings.

Super-heavy Nazi architectural experiment.

Between Neo-Pagans and Neo-Nazis, these strange rock formations have a curious cult following and a very strange history.

The bunker where Hitler took his own life is hidden under this deliberately ordinary parking lot.

Gardens representing parts of Asia, Europe, and the Mid East are tucked away among the Soviet-style buildings in East Berlin.

The site of the famous Nazi book burning campaign of 1933 remembers its "Night of Shame".