The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

Nevada's largest cactus collection stands outside a candy mogul's small factory.

Experience a charming 1930's version of "infotainment."

In the middle of an extremely unforgiving and desolate high desert is the most secret military facility in the world.

At this research institute, the chile is king.

This quirky hot springs town known to locals as "T or C" was named after a radio show.

This is one really big nut.

These Pre-Columbian petroglyphs contain representations of birds, deer, hunters, and even some early Native flute players.

This fast-food outlet is the only space and UFO-themed McDonalds in the world.

Legends surround this jagged rock formation in the New Mexico desert.

If drivers cross the rumble strip on this stretch of Route 66 at just the right speed it plays "America the Beautiful."

A museum dedicated to the alleged Roswell Incident.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

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

The highway's southernmost spot is a beloved local attraction.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.

Location of a reliquary containing bone fragments of 18 saints.

The unique collection includes bronze cast handprints of some of America's most famous astronauts.

A building so large that it has its own weather.

This abandoned NASA launch site is now a memorial to a trio of astronauts who were killed there.

Intertwined, interspecies trees which locals believe can grant boons to lovers.

A monument celebrating the idea of reaching inaccessible places.

An 18th-century Spanish watchtower made entirely of seashell and concrete.

North Central Florida's largest flea market and a weekend roadtripper's dream.