The medieval castle built as headquarters for the Pope's secretive Knights Templar.

Picturesque intersection of witchcraft and ancient Christianity.

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

Every year locals tumble 650 feet down to the bottom of the hill chasing a Double Gloucester cheese.

These "bridges" help confused bats cross the road.

Nestled in the mountains of Portugal is a tiny village made almost entirely of schist.

One part local history, 99 parts gruesome haunted house.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

The oldest working mechanical clock in the world.

Famously misunderstood wonder of the ancient world

This picturesque horseshoe weir was first built in the 1600s to prevent flooding in the town of Bath.

This well-preserved Cistercian Abbey in a romantic pastoral setting has inspired artists like the poet Wordsworth.

This hilarious English intersection is an automotive whirlpool.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

Britain's answer to the NSA is based out of this deliciously-named circular headquarters.

Overshadowed by other, more famous Maltese catacombs, this ancient burial chamber has one of the best examples of a ritual agape table.

The remains of a 1st-century aristocratic Roman town house featuring beautiful well-preserved mosaics.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

The fishing boats that moor in this small lagoon enter and leave through a tunnel to the sea.

A hidden tunnel of bones in one of Malta's oldest churches.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

This beautifully verdant lagoon is tucked below a massive volcano in a crater atop a black pebble beach.

Partially collapsed lava tube and cave system complete with concert hall, underground pond, and unique albino crabs.