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

The most visited, and possibly most controversial, museum in Germany.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

This automated sculpture of two men peeing will spell out text messages with their micturition.

A floundering Polish shipyard was once the soul of the Solidarity movement that capsized communism.

Modern art commemorates one of the first military actions of World War II.

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

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

A botched 18th-century canal silenced one of Sweden's most magnificent waterfalls.

The city that saw the birth of Sweden is now home to an impressive collection of work from its favorite artist.

Despite the groans of archaeologists, this astounding groups of Bronze Age petroglyphs have been painted red for tourists.

The second oldest anatomical theater is housed in a museum of curiosities.

Ancient burial grounds of the wealthy.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

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

18th century opera in its original splendor.

This encrypted monolith protected a secret of Norse mythology by hiding in a church wall for over a millennium.

The northernmost point in Denmark is a turbulent sandbar created by two clashing seas.

The world's biggest floating museum in Gothenburg, Sweden.

A Gothic-inspired fish market is Gothenburg's best place to find loaves and fishes.

One of the world's few mounted blue whales, its jaws are hinged open allowing visitors to descend into a lounge.

Old Danish castle immortalized in Shakespeare's Hamlet.

According to legend, this boat-shaped henge is built over the grave of a mythic king.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.