Once the home of a hermetic monk, this cave now houses a small church.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

Locals dubbed it the "Owl Building" because of its bird-like appearance.

The king of U.S. high points towers over every other peak on the continent.

One day a year it is legal to jump off of this astoundingly tall bridge that spans an Appalachian gorge.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

The final resting place of two (or three) presidents, one vampire, and 18,000 Confederate soldiers.

Home to the deepest rift anywhere on Earth.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

A geological mystery on Camelback Mountain.

A former major munitions plant that has been converted into a sprawling art space.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

A small park on Bourbon Street features life-size bronze statues of New Orleans musicians.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

The once highest point in China blends symbolic design with a kick of adrenaline.

A sculpture of the famous photograph stands on San Diego's "Greatest Generation Walk."

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

The only Bahá'í house of worship in North America and one of only a handful worldwide.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

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 only road through the heart of Glacier National Park.