A castle from the Holy Roman Empire that hosts traveling youth... in its stables.

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

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

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

Towering at a height of over 30 meters, this turn-of-the-18th-century landmark is the tallest temple in Nepal.

Jumping-off point for a climb up Mt. Everest is the most dangerous airport in the world.

Last stop before the top of the highest peak in the world.

One of the largest Buddhist stupas in the world keeps an eye out in every direction.

Sacred Buddhist home of some spiritual monkeys.

The abandoned palace stands as a wounded but proud beacon of Afghan hope.

What was once supposed to be the symbol of a shining Afghan future is now a bombed-out ruin.

Look closely and you’ll notice that the color changes a third of the way up the tower.

The "lovely red Vega" of the legendary record-settling pilot.

Go inside to really appreciate this 500-year-old technological masterpiece.

Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

Buy your friend a drink or staple some cash to the wall for the next guy at the Salty Dawg Saloon.

While not recognized by Guinness, this chocolate waterfall is likely to be the world's largest.

North America's first frozen mummified remains of an ice age steppe bison, the 36,000 year-old mummy named "Blue Babe."

This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

This WWII-era military installation once held an entire city within its walls - now, its walls are falling down.

Four-story concrete hotel never opened to customers.