18th century anatomical amphitheater of the Royal College of Surgery of Barcelona.

Sweden's "good old days" painstakingly re-created in a model village.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

Mysterious Spanish catacombs of unknown origins.

Mountain where Jesus was first tempted by the Devil.

Vibrant street art created with mixed media.

Historic medieval fortified city in southwest France.

World's first "penitentiary," meant to be humane, drove men insane.

The only castle in North America to ever house European sovereigns.

The tower was originally used as a chimney for the waste incinerator of St. John's Precinct and Market.

Huge masonic hall in Philadelphia with lavishly themed rooms.

The earliest known map to show America, discovered by accident at a Paris bookshop.

London's smallest police station is barely the size of a phone booth.

The Bristol Camera Obscura housed in an ancient windmill.

A Gothic cathedral created from volcanic rocks.

Eighteenth-century home, where Herschel discovered the planet Uranus.

Mural made of 100,000 pieces of hand blown glass, and until recently, the largest glass mural in the US.

Commonly acknowledged as the only public monument to the Devil himself.

Early habitat dioramas and home of the elusive gaff, the skvader.

Pyramid shaped monument with a tall tale attached.

An ancient Egyptian temple in the middle of Madrid, Spain.

It houses the remains of a 17th-century version of the Titanic.

An accidental trick of light casts the perfect shadow of a pilgrim of the Camino de Santiago against the cathedral wall.