This hanging crocodile is thought to be the "dragon" that once plagued a Czech city.

Mummified monks and the accidentally interred, in a 17th-century crypt.

Berlin's old airport.

Op-art architecture designed for happiness.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

Legends surround an ancient tree trunk riddled with nails for good luck.

The beautiful baroque library of the Hapsburg empire.

The final resting place for the remains of 143 Habsburg royalty.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

Museum dedicated to the terror regimes of Hungary.

The home of the Dead Sea Scrolls is an abstract modernist dream.

The prototype for all Nazi concentration camps.

Cold war icon and onetime "hole" in the iron curtain.

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

The land is home to swimming ponies and a legendary 18th-century treasure.

The fastest mail service in the west is tracked and memorialized along this 1,400 mile trail.

A Texas museum filled with Broncos and Betties.

Ride the subways of yesteryear.

The very first subway station in New York City is beautiful, decked out in chandeliers, and ... abandoned?

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.

A Natural History and Science Emporium.

Visit the monolithic tomb of America's most famous general.

The former home of Samuel Clemens and family remembers the happiest period of the author's life.