All that's left of the quintessential "cabin in the woods."

Sparkling, calcite-covered skeletons of children who may have been sacrificed to appease an angry god.

The remnants of an archaeological camp stand within Tikal National Park.

A natural gas leak provides a flickering flame beneath a waterfall.

A popular place to pick up prehistoric coral fossils from the time when Michigan was an ocean.

Ancient petroglyphs discovered only after a massive fire swept across Michigan in the 1880s.

The largest earthwork effigy in the world.

This old cement mine has been used as everything from a mushroom farm to a recording studio.

This crumbling Portuguese ruin overlooks the populace it once ruled.

This abandoned Slovenian military barracks has become a punky-political art squat.

A miniature train-ride through Slovenia's largest cave system.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

This one-time health resort was used by aristocrats around the world.

This massive subterranean fissure is known as the "underground Grand Canyon."

An small and easily overlooked archaeology museum chock full of Egyptian artifacts.

A historic London cemetery now serves as a nature park incorporating gravestones & memorial statues.

A vast overgrown cemetery, once known as one of London's "Magnificent Seven."

The curios of pharmacist and collector Henry Wellcome.

The only university zoological museum in London houses extinct animals, bizarre natural history specimens, and a Micrarium of microscopic creatures.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

Mausoleum and Holy Seat of Antiochus I of Commagene.

An abused and forgotten metropolis, abandoned for centuries.

This ancient subterranean megalopolis is known for the hot oil traps that were installed above each of its entrances.