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

This abandoned amusement park was built on a site with a dark history.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

The first declared National Monument in the United States.

The land is full of geologic eye candy, such as otherworldly spires, mushroom-shaped hoodoos, and prehistoric fossils.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

Dramatic river bend surrounds a natural red-rocked pedestal.

Most-visited and most-photographed slot canyon in the American Southwest.

Sleep in a glass pod dangling off a cliff.

A forgotten monument to Yugoslavian freedom.

Bridge that died in war and was resurected.

Sculpture designed by Turkish artist and professor Mehmet Ali Uysal.

The first park built over a freeway is a brutalist masterwork.

This former coal gasification plant found a curious second life as a popular public park.

Brawny guys rolling around in oil is the oldest regular sporting event besides the Olympics.

Iran's colorful terraces are a rare geological masterpiece.

Ancient structures used to make and preserve ice in the deserts of Persia.

This bridge is embedded with a giant steel dragon that breathes fire from its mouth.

This spectacular bridge supported by two gigantic hands looks like something out of a fantasy universe.

Believed to have once stored either human remains or rice wine, thousands of mysterious stone jars lie in ruin.

Nine nice parcels of land along a flight path offer a quiet respite... until a plane soars overhead.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

La Monte Young and Marian Zazeela's "Dream House" will immerse you in an ever changing world of sound and light.

China’s breathtaking futuristic library is lined floor to ceiling with fake books.