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

A reproduction of earth's many biomes.

Better known as the "Body Farm," this unique research facility has been studying how human bodies break down since the 1980s.

Rustic natural hot springs in the deciduous rain forest.

Tour the sci-fi-esque reality of governmental disease management.

Breathtakingly blue walls shimmer inside the "Glacier Behind the Town."

Hundreds of glow-in-the-dark objects light up a museum in a historic zinc mine.

Make your reservation to have coffee with some kitties.

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

No one knows how this Pacific Northwest spruce tree came to have so many trunks.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

Oregon's unexpected high desert, displaying layers of time in a colorful show.

This lab's maddening silence is good for business but bad for sanity.

Welcome to old Florida, where a 1940s mermaid show is still enchanting visitors.

This historic "City of the Dead" lies prominently in the center of New Orleans' famous Garden District.

The secret city built by the Manhattan Project.

Each year these high desert hills are absolutely covered with poppy flowers in a surreal show of nature.

A modernist landscape of water and sci-fi concrete.

This geothermal hot spring hides beneath a slowly growing mineral dome.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

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

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

A stunning, two-tiered waterfall made famous by poets, artists and the legend of a ghost dog.

One of the world's oldest and most massive living organisms is a grove of quaking aspens.