This shallow cave got its name from copious amount of human bones found inside.

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

This national park on the shore of Lake Michigan features remarkable dunes that lie at the heart of a Chippewa legend.

Meet manatees face-to-face at this zoo for native species.

Manatees congregate around a power plant's discharge canal where the water is especially warm.

Grab a slice of pizza next to the remains of the "human monkey" who ran for mayor.

Found: Garden of Eden in Miami-Dade County, Florida.

Located within a historic park, the beacon is the oldest standing structure in Miami.

Over 120,000 curious objects that have shaped our modern world.

Peruse rare tomes like poetry bound in pearls or books with branches and berries growing out of their spines.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

The tunnel under the Capitol Building where Congress takes out its trash.

Look closely and you’ll notice that the color changes a third of the way up the tower.

An overlooked memorial honoring the local Washington residents who died in World War I.

Perhaps the most scandalous statue of America's first president.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

The house where John Wilkes Booth conspired with his co-conspirators.

The site of the climactic scene from the classic horror film is now a historic landmark.

Washington's iconic carousel has a nice piece of Civil Rights history.

This 5-by-6-foot wooden hut is the smallest historic post office in the U.S.

The world's largest occupied bat houses hold hundreds of thousands of flying mammals.

You might know it as the Overlook Hotel, but the inside is not going to be familiar.

Despite a legend that says this highest peak in Oregon was climbed in high heels, scores of people have died on its slopes.

According to legend, you must remain completely silent while passing this man-made mound or suffer the consequences.