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

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

Dramatic river bend surrounds a natural red-rocked pedestal.

A clear blue swimming hole with hidden caves, still unexplored.

The superstar of Cold War nuclear bunkers has been featured in countless films but is now barely operational.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

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

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

Peace Park and the Atomic Bomb Dome.

A plaque marks the site directly below the mid-air detonation of the atomic bomb over Hiroshima.

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

The "lovely red Vega" of the legendary record-settling pilot.

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

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

Part of a WWII submarine is lurking outside the Washington Navy Yard parking lot.

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

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

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

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

There’s a special club house at the top for the bell ringers.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

Largest Roman Catholic church in North America.

The national park was once a plantation estate.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.