There has been an astronomical clock on this spot since the 14th century.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

A museum dedicated to the alleged Roswell Incident.

Wall to wall taxidermy at Denver's oldest and most exotic steakhouse.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

20-foot tall lamp mumbles Swedish to celebrate the holidays.

This chimerical bridge/tunnel appears to dead end right into the sea.

Swedish skyscraper with a 90° twist.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

Funhouse of found art and participatory sculpture.

20,000 pieces in a Frank Gehry-designed building.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

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

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

The somber sculptures commemorating Irish Famine on the river Liffey in Dublin.

The modern birthplace of Irish freedom.

The celebrated eyesore created by starry-eyed sweethearts.

Ancient serpentine sacrifice holder that has stood the test of time.

A marvel of Byzantine engineering under the streets of Istanbul.

The Guardian of Tallinn.

In Florence's great Duomo, a 26 foot fresco honors a mercenary famous for attacking Florence.

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