A unique botanical garden housed in three giant geodesic domes.

What was once a presidential estate is now an exotic menagerie and home to the Budweiser Clydesdales.

The fifth-longest suspension bridge the world, connecting one Michigan peninsula to another.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

A multi-storied adobe complex has been inhabited for more than a thousand years.

The oldest continuously occupied public building in the United States.

A small side chapel in Santa Fe's basilica is home to the oldest statute of the Virgin Mary in North America.

Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

This monumental Jesus is often referred to as "Our Milk Carton With Arms."

An extravagant western hotel where every floor is the "ground floor."

The Ozarks' strangest dwelling.

This haunted hotel built on natural springs once served as a hospital for a quack doctor promising a cure for cancer.

This futuristically sylvan church is a glass-enclosed marvel of modern architecture.

An elaborate Mayan city shrouded in alien conspiracy revealed the tomb of Pacal the Great.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

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

Every equinox this Maya pyramid puts on a spooky ancient light show.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

An epic sculpture depicting a wagon and straining oxen.

This beautiful example of neoclassical architecture is one of Uruguay's most treasured cultural gems.

The design of the Palacio Salvo has been described as "a lighthouse on top of a building."