A Black Forest cuckoo clock theme park features one timepiece big enough to walk inside.

The prototype for all Nazi concentration camps.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

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

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

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

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

Giant marble phalluses on the sacred island of antiquity.

The hallucinogenic center of the ancient world.

The seat of Buffalo government is a gorgeous Art Deco palace.

The dairy farm in upstate New York where nearly half a million people gathered for three days of peace and music in 1969.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

An eccentric priest's tribute to George Washington, this chapel tells the story of the American Revolution.

The rusting remains are visible sticking out of the waters of the Delaware Bay.

An abandoned quicksilver mining town surrounded by the Big Bend parks.

A recreated Stonehenge stands in a country field, complete with Easter Island moai heads standing as sentries.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

This distinctive Crescent City tradition dates back to the days of horse-drawn carriages.

The world-record holder for the longest bridge stretching continuously over water.