One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A beautiful geyser under environmental threat.

The first declared National Monument in the United States.

This historic hotel on Bathhouse Row in Hot Springs National Park has a storied history of gangsters and baseball greats.

Two gushing waterfalls of hot spring water within a block of each other.

Mobsters came for a soak in the hot springs, and stayed for the illegal gambling and bootlegging.

Why walk on this historical site when you can zoom down instead?

This exemplar of modernist architecture is meant to captivate and inspire students of the Cooper Union.

Touching mementoes from those who didn't make it back from World War I still hang in one of New York's oldest bars.

Named the fifth most beautiful building in America in 1885, this former courthouse boasts the best view in the Village.

The oldest operating apothecary in the US has treated everyone from Thomas Edison to Mark Twain.

The best way to get a sneak peek at the movies.

This slender three-story building has also had several famous residents.

Phil Mortillaro uses keys to bring art back to the Village.

An aptly-named street near the birthplace of the modern LGBT rights movement.

The first piece of public art dedicated to LGBT rights.

One of only two commuter aerial tramways in the United States.

Elevated freight railway turned wildly successful urban park.

Try not to get slimed in Tribeca.

A bizarre roadside attraction and the first instance of miniature golf in the world.

This large cave is a summer home to thousands of bats and has a rich history dating back to prehistoric times.

A natural sandstone bridge hidden in the Sewanee forest.

An ancient cave system in Tennessee’s Appalachian foothills converted to a 1,200-person music venue.