The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

The tomb was guarded by soldiers from both sides of the war, and some left their initials carved in the brick.

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

The Corinthian columns that towered over Abraham Lincoln’s inauguration stand proud.

Home to a vast and influential collection of Shakespeareana.

On the Fourth of July this area will transform into a Pompeii-like storm of falling embers and ash.

The rogue roots are gradually consuming some of the historic marble grave markers.

The romance of early commercial flight still fills this Art Deco destination.

The only Leonardo Da Vinci painting in the Western Hemisphere.

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

Pluto is still considered a planet in Ithaca, New York.

A reproduction of a giant humanoid "fossil," a hoax buried locally for construction crews to find and gain national attention.

This Upstate New York park squeezes a lot of history into its two-acre triangular space.

The only U.S. Senator to die on the field of battle is buried in San Francisco but memorialized at Balls Bluff Regional Park.

This extravagant Art Nouveau rest stop features a million-dollar view of the Columbia River.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

Massive still life just off the highway in Kansas.

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

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

These elusive, isolated rodents evolved into a distinct, locally iconic subspecies.

This Native American settlement dates back to the Pueblo II period.

A motel dedicated to Southwestern nostalgia.

See massive fossils that are over 200 million years old in northeastern Arizona.

Berkeley Springs State Park boasts the nation's only monument commemorating presidential bathing.