A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

One of the steepest streets in the United States makes an intriguing challenge for cyclists.

An unnatural lake in a naturally beautiful setting.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

Colorful Native American paintings are hidden within this small cavern.

Ancient human, animal, and geometric figures drawn in the earth.

An extensive collection of ancient Egyptian artifacts and mummies.

Once thought to be the oldest living tree in the world, Methuselah was germinated before the Egyptian pyramids were built.

This small New York museum examines Chinese history from its origins right up to its arrival in the city.

Dedicated to preserving the history of free Black communities in Brooklyn and beyond.

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

This semi-hidden Manhattan restaurant is based out of a loading dock.

Hundreds of antique bank vault locks on display in New York City.

The oldest bibliophilia club in America, with exhibitions on historic books and graphic arts.

An unassuming secret door once led to a legendary watering hole.

Here lies Lilly E. Gray, an alleged "victim of the beast," but the reason long remained a mystery.

A beautiful geyser under environmental threat.

The only completed wing of Utah's first capitol is filled with artifacts and odd stories about its past.

Where a guard killed nine German prisoners during one of the worst 20th-century POW camp massacres in U.S. history.

A new kind of theme park for adults off the Las Vegas Strip.

The rocks in this arid basin leave trails of movement behind them.

A massive hydrovolcanic explosion left a half-mile wide crater in Death Valley.

An abandoned Jazz Age dream home and con man's hideout in Death Valley.

This magnificent, quirky home sits atop a literal gold mine in the middle of the Nevada desert.