Rippling sand dunes frozen in the Arizona rock.

The world's largest military aircraft cemetery.

A mini Wrigley Field for mini baseball players.

Dig for your own trilobites in this goldmine of invertebrates.

A gargantuan crystal kingdom.

A place to eat for on-the-run agents and espionage enthusiasts.

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

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

270 million year-old forest of stone.

A pop-culture attraction outside of Dyersville, Iowa, hits a home run.

Fabulous formations, weird and wonderful wildlife.

Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

The Avenue of Mausolea is a series of grand palatial tombs.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

Named after a bandit and the star of several Hollywood prehistoric landscapes, these sandstone formations are a historical part of the Los Angeles natural landscape.

The only Bahá'í house of worship in North America and one of only a handful worldwide.

More gold than anywhere else, ever.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.