A labyrinthine underworld of tunnels and caverns hides beneath the city.

One of the oldest producers of hand-folded fortune cookies still uses its original secret recipe.

An assortment of armored tanks and Howitzer cannons in the middle of the Sonoran Desert.

A trash dump made beautiful by nature's power.

Run by members of the Tohono O'odham Nation, this community farm nurtures traditional desert cultivars.

These eerie outliers of the lightning bug family glow a mysterious blue color.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

The ancient tomb acts as a calendar that keeps perfect time.

The oldest stone house in Paris was built by its most famous alchemist.

One of America's first dinosaur parks gives a window into Depression-era paleontology.

The mummified heart of a saint lives on in this church—after a brief hiatus when it was stolen.

One of the oldest Mexican restaurants in the United States air-dries its trademark beef in a dangling outdoor cage.

A natural history wunderkammer in the middle of the desert.

Legend says train robbers stashed their gold within the depths of this unusual cave.

During World War II this was the site of an "honor camp" used as a prison for draft dodgers, Native American conscientious objectors, and Japanese-Americans—including a man who brought his case against the camp to the Supreme Court.

After a short-lived attempt to bring America in line with the rest of the world, this road was left in metric.

Ask nicely, and stewards of a centuries-old charitable tradition will give you free bread and beer.

This cathedral's stained-glass patchwork of psychedelic colors and shapes was put in place long before the swinging 60s.

This silent sentry in the crypt below a large Gothic cathedral is often knee-deep in water.

A medieval replica of King Arthur's legendary table, the Round Table hanging in Winchester Castle was decorated by Henry VIII.

A roadway designed for a visiting monarch.

This bird-shaped rock formation defies gravity, time, and classification.

Classy up your Big Mac with bow-tied servers and chandeliers at the world's fanciest McDonald's.

This church on a Tohono O'Odham reservation has stood since 1797.