This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

A spherical "micro-nation" in the heart of Vienna.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

Apartment complexes built into huge repurposed natural gas tanks.

The topiary maze at the Habsburg hunting lodge.

Baroque celebration of the end of the Great Plague of Vienna.

Remnants of a storybook amusement park hidden behind a strip mall.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

Eccentric concrete mansion and museum designed and built by hand from the inside out.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

Golden and naked, the figure that was once the highest point in New York is all that remains of the second Madison Square Garden.

The home, museum, and death site of Kodak's influential founder.

An acoustic anomaly with a mysterious cause.

Nature's biggest mammal swims in landlocked Oklahoma.

This Philly cemetery is the eternal home of many famous area residents, including Rocky Balboa's wife.

What began as an art installation is now the private drinkhaüs for a brewery's employees.

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

The land is home to swimming ponies and a legendary 18th-century treasure.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

Huge masonic hall in Philadelphia with lavishly themed rooms.

The first American department store, and home to the largest operating musical instrument in the world.

A scenic fort on the harbor protected Philadelphia from an attack that never came.