The prototype for all Nazi concentration camps.

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

Climb inside an iron crystal magnified 165 billion times its normal size.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

This incredible stone temple is a monument to death, victory, and fantasy architecture.

A sprawling Baroque park with 300-year-old hydro-pneumatic waterworks.

A 131-year-old wunderkammer of Texas history.

This grimly-titled Texas cemetery is all that remains of a Wild West settlement with possibly the worst name.

What do a giraffe, an elephant, and reasonably priced steaks have in common? This roadside restaurant filled with exotic taxidermy.

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

Controversially claiming the title of world's biggest bass drum, UT's Big Bertha was once made radioactive by the Manhattan Project.

A sculpture of the famous photograph stands on San Diego's "Greatest Generation Walk."

Home to more than 13,000 pieces of war memorabilia and military equipment.

Site of the 1879 Cheyenne Outbreak and the site where famed Sioux chief Crazy Horse met his fate.

An experimental, automotive replica of Stonehenge.

This erect, phallic geological spire wasn't always named so domestically.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

Macabre astrological automaton clock dating to the late 1400s.

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

A popular swimming hole that hides one of America's most deadly diving spots.