The world's oldest surviving anatomical theater, where "the dead are pleased to help the living."

Twelve natural mummies are displayed in the crypt of this former monastery school.

A fortified city, home to a remaining population of five families

The largest game reserve in Africa is home to thousands of species but refuses to house humans.

A flooded Mexican cave that hides a river beneath the water.

Wonderfully preserved Victorian factory, complete with a preserved steam powered engine house.

A Texas-sized particle collider that was abandoned due to its Texas-sized budget.

A wooden hut from the Heroic Age of Antarctic Exploration.

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

A remains of a stone shelter are a reminder of "The Worst Journey in the World."

This famous city eluded concrete detection until the early 2000's.

A centuries-old fortress city lies in ruin.

Sacred Buddhist home of some spiritual monkeys.

Thanks to the building of a life-giving reservoir, part of the Great Wall of China is now a dive site.

Bizarre Cavern.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

Ruins of a German Castle on top of a towering stone pillar.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

Largest site of dinosaur footprints ever found includes more than 5,000 tracks.

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

An emerald-green grotto just a short trip from Austin.

One of the oldest living oak trees in the Southeast.