The largest hewn stone in history.

A Roman temple perched over an Italian town, forgotten several times over.

The meteor that sealed the fate of the dinosaurs landed at this site, one of the largest impact craters in the world.

A field of whimsical floats, where all of your favorite childhood stories have been put out to pasture.

A sprawling network of century-old subterranean catacombs lies beneath a nondescript suburban home.

These winged Maya figures are the subject of speculation and conspiracies.

This popular cave pool is truly magical, despite the crowds.

These azure waters were thought to lead to the Mayan Underworld.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

Few of the many visitors to this resort town know of its hidden Maya ruins.

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

The ruins of an important pilgrimage destination for worshippers of a Maya fertility goddess.

One of Mexico's least-visited archaeological sites is tucked away inside a theme park.

Underwater art project will double as a massive artificial coral reef to help regenerate the damaged ecosystem.

A small collection of iguana-infested ruins hides amid Cancún's bustling hotel zone.

An ancient system of freshwater caves filled with animal bones, including that of species long-extinct.

This former tuberculosis research hospital endeavored to cure the dreaded disease with fresh air and positive attitudes.

The metal truss bridge served as the sole entry point to an "isolation island" for smallpox outbreaks throughout the 1870s and early 1940s.

Prison made famous by The Shawshank Redemption has been out of commission since 1990.

Beautiful mostly-abandoned town only accessible by sea-worthy boat or plane.

The ruins of this Alaska gold mine form a gorgeous ghost town.

Breathtakingly blue walls shimmer inside the "Glacier Behind the Town."

The ancient tomb acts as a calendar that keeps perfect time.