Massive volcano in the Andes is the farthest point from earth's center.

An ethereal glowing blue ocean cave in Croatia.

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

Yugoslavia's biggest underground airport lies in ruins.

Virgil's many-mouthed gateway to the underworld.

A gargantuan crystal kingdom.

The ruins of an ancient island city built atop a coral reef in the South Pacific are spectacular and strange enough to have inspired H.P. Lovecraft.

Astronomical observatory above Lake Titicaca.

A massive underwater sinkhole made famous by Jacques Cousteau.

A walk through the historic city center, under the streets of Seattle.

"Respectful to the dead, safe and sanitary to the living, dedicated to the Genius of Memory..."

The oldest stone house in Paris was built by its most famous alchemist.

Notorious artist squat renovated into legal studios.

Underground hospital complex constructed by slave laborers during the German occupation of the Channel Islands.

A site where “the ravages of the war are more striking…than any other place in contemporary Spain.”

This star-shaped military outpost is now simply trying to protect itself from neglect.

Abandoned 18th century weapons factory in the Aezkoa Valley.

The deserted remains of a luxury hotel turned hospital ward.

Houses are tucked between, on, and underneath giant boulders.

A huge cathedral single-handedly constructed by one eccentric monk.

This abandoned naval battery stood at the ready as recently as the 1980s.

An abandoned Indian-inspired mansion.

One of only two towns in Israel populated by Circassians, a sect of Sunni Muslims who are also devoted to Israeli military service.

Ghost Town in the Demilitarized Zone of the Golan Heights.