At 705 feet high, Brazil's "House of Stone" is the largest cave mouth in the world.

Visit this playground of waterfalls, caves and sinkholes.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

A spectacular cave and a beguiling lake.

The hallucinogenic center of the ancient world.

The historic tower houses of this nearly abandoned Greek town have been compared to the spikes on an iguana's back.

This remarkable cave was discovered after a shepherd watched bees enter and exit through a small fissure.

This town named for the ancient God of War is home to fewer than a thousand people, but it's the birthplace of the Greek Revolution.

Pompeii's less famous neighbor is still revealing her secrets.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

This frequently-photographed waterfall takes only a short hike to visit.

The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

Hellam Township is reputed to feature seven remote gates, which when passed through in the right order, open an entrance to hell.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

Cold War missile launch site which has been converted to a public park.

The pedestrian traffic signals in Brazil's teeming metropolis light up with clues to nearby landmarks.

Site full of incredible prehistoric paintings and archeological findings.

High plateaus and beautiful waterfalls frame this ecologically significant nature preserve.

Site of the largest impact event to occur over land in Earth's recorded history.

This hospital fell into ruins after failing to act as the advocate for the mentally ill it was designed to be.

A Scottish manor with a history of mysterious fires, magic, and eccentric tales

This field of half-buried stone crosses was the burial place of a sect of heretical gnostics.

This private island is still in the family after a 400-year history including a witch hunt and a pirate.

A mysterious air force base built to resemble a Long Island fishing village.