Incredible labyrinth of man made caves.

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

One of the oldest of its kind.

A retired firefighter created this contraption so he and his family wouldn't die if accidentally buried alive.

The severed head of a 17th-century Irish martyr lies within an intricate golden shrine.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

An incredibly well-preserved piece of ninth-century Viking poop.

America's oldest Eastern European synagogue provided the immigrants of crowded Lower East Side tenements a space of sanctuary.

Experience what life was like in Ireland during the Viking and medieval ages.

The 80-foot tire that looms over Michigan's I-94 was once a Ferris wheel in the New York World Fair.

The Beaux-Arts aquarium boasts a vast collection of saltwater and freshwater fish on an island in the Detroit River.

These enduring murals depicting a distinctly Marxist tribute to capitalism could not even be defeated by McCarthyism.

Controversial tribute to the heavyweight champion boxer who grew up in Detroit.

To truly appreciate Detroit's landmark skyscraper, you have to step inside.

This enormous World War II relic is one of the largest wooden structures in the world.

Meant to be a lavish presidential home, the palace became a symbol of the fall of South Vietnam.

Witnesses claim the Virgin Mary statue outside the church once mysteriously shed a single tear.

This neon landmark has been posing this deadpan question to follicly-challenged Dubliners for over 50 years.

This network of narrow, medieval passages has the most delightful name.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

Home to three historic ships from the age of Vikings.

Housing the famous Norwegian ice-defying 19th century polar exploration ship.

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