The secret city built by the Manhattan Project.

A failed utopian experiment for British expats in the American South is now a Victorian village frozen in time.

Mass graves and Victorian monuments mark the history of Memphis in this 19th century cemetery.

Yo, Adrian!

World's first "penitentiary," meant to be humane, drove men insane.

This elaborate towering structure was once famed for its revolutionary height.

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

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

A mine fire has been burning under the deserted town since 1962, but this church is still going strong.

One of America’s oldest and spookiest hotels, thanks to the residency of ghosts, dead presidents, and Alfred Hitchcock.

The rusting remains are visible sticking out of the waters of the Delaware Bay.

Rising out of a clearing in New Jersey's Pine Barrens is an Aztec-inspired monument to the "Lindbergh of Mexico."

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

Mile-long cave system near Great Smoky Mountains.

Mountain known by the Tillamook Tribe as "the place of the supreme deity."

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

400 million-year old limestone caverns nestled in the Ozarks served as shelter and a hideout for cultures throughout North American history.

This house was largely built out of hundreds of thousands of discarded glass embalming fluid bottles.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

The biggest solar telescope in the world helps reveal the secrets of our sun.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

At 207 feet, one of the world's longest continuous escalators.

A snapshot of the city's fascinating voodoo culture.