A deserted hodgepodge of experimental structures designed by nearby university students.

A massive volcanic plug is now a protected area that hosts a number of bird species.

The unbelievably opulent home built for an infamous newspaperman.

A hotel and restaurant serving as the mecca of kitsch.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

The highest point in Arizona is an oddly snow-topped peak within the otherwise arid state.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

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

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

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

In Tucson a giant metal snake helps pedestrians cross a busy highway.

The world's largest military aircraft cemetery.

America's only nuclear missile silo open to the public.

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

A museum dedicated to the history and art of staying clean.

The only road through the heart of Glacier National Park.

New fungal and bacterial species call this deadly lake home.

An entire town preserved as a historic landmark.

The first declared National Monument in the United States.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

An experimental, automotive replica of Stonehenge.

A true roadside icon standing on the same plains that the herds once roamed.

This abandoned horse racing track was an exercise in hubris from its inception.