Supposedly this Ethiopian chapel holds the Ark of the Covenant, guarded by virgins who cannot leave the building.

Reaching the "Church in the Sky" requires scaling the cliff face of a sandstone pinnacle with a 650-foot drop.

The hottest place on the planet.

Ethiopia's "smoking mountain" is in one of the hottest regions on the planet and is home to two lava lakes.

An Ethiopian "Jerusalem" featuring a church hewn out of a single rock.

This indie movie theater is one of only three surviving Mayan-themed theaters designed by “Detroit’s greatest theater architect.”

Advice-columnist's bell tower, paid for with pennies.

A series of 33 stone markers maps an ancient 55-mile transportation route.

Winter weather reveals a large Italian marble crucifix drowned beneath Lake Michigan.

This Neolithic passage tomb forms part of a World Heritage Site.

This natural sea arch highlights Ireland's rugged coastal beauty.

A massive Celtic cross secretly growing in an Irish forest.

Eat like a bird in a bamboo nest.

These jagged limestone blades cut out through the canopy of the jungles of Borneo.

Some locals believe the fabled lost gold of General Yamashida is hiding somewhere beneath the city.

An ancient quarry rediscovered by a dog and claimed by biblical kings, a German cult, and the Freemasons.

A serene desert oasis speckled with ancient artifacts.

A hyper-remote desert cave dramatized in "The English Patient."

The ruins of an ancient Zoroastrian Tower of Silence believed to be the earliest example of the traditional funerary practice.

Former island in the Aral Sea used to be a top-secret Russian bio-weapons facility.

The first version of this stalwart construction appeared around 3,000 years ago.

This ancient Silk Road outpost overlooking the Wakhan Valley is miraculously still standing.

This medieval citadel once guarded the western entrance of the Pamir Highway.

The largest dam in the world and the site of a potential disaster.