The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

For those with no fear of heights: a skywalk 4,700 feet up on a Chinese mountain.

A total of 999 stairs lead visitors through a massive hole in a mountain known as the Gateway to Heaven.

Largest collection of mounted dinosaur specimens in the world.

This psychedelic tromp l'oeil seems to be beckoning drivers to crash into a wall.

This titanic steel chain linking two buildings was installed without permission but instantly beloved.

Paths are maintained, but trees have taken over plots.

Once the most flame resistant building in the country, the South Carolina Historical Society building was almost burnt down in a fire.

A multi-storied adobe complex has been inhabited for more than a thousand years.

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

Railroad came. People came. Railroad left. Town died.

You have to love a museum with a truly dedicated focus. A focus on Superman, for example.

Enormous lake at the bottom of a unique cave system.

This structure among the trees was the result of divine inspiration.

Labor provided by Great Depression-era programs restored these 25,000 acres in Tennessee.

The last Americana on Route 66.

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

A former utopian healing center created by a huckster and built by derelicts.

The "world's biggest dinosaur" once housed a creationist museum in its abdomen.

Oldest building in California still in use.

Mexican food and folk art.

Megachurch turned Catholic church comprised of 10,000 glass panes.

The biggest drug trafficking passage between Mexico and the U.S.

A US military accident created the legends behind this Mexican version of the Bermuda Triangle.