It's good luck to be mocked by this monkey.

A Black Forest cuckoo clock theme park features one timepiece big enough to walk inside.

A striking 12th-century-style castle built on the edge of a cliff.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

A small but immensely extravagant palace built by the "Night King."

The fairy tale castle of the "fairy-tale king."

Every hour the doors open to reenact the legend of the heroic mayor who saved his town by drinking a gallon of wine.

The prototype for all Nazi concentration camps.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

A famous hotel houses an impression collection of mini dioramas and giant doll houses.

One part local history, 99 parts gruesome haunted house.

Built to repay the sins of the father, this church is home to one of the most valuable works of Western art.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

The mountaintop inspiration for Umberto Eco's "The Name of the Rose."

This picturesque Umbrian city has a subterranean side that has long remained hidden.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

A Nesting Doll of Churches.

Jesus' footprints and the first catacombs in the world.

Pilgrimage site for star-crossed lovers.

Go inside to really appreciate this 500-year-old technological masterpiece.

2300-year-old Roman road connecting the empire.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

Canada's subterranean Cold War museum has doubled as a movie set.