A six-ton, 12-foot-tall concrete prairie dog is touted as the largest in the world.

Stroll through a wonderland of stupendous moss-covered trees.

This angular Dwarven tunnel cuts through a mountainside in Glacier National Park.

A community of collapsing homes more than a mile out from the Florida coast.

A gothic palace of endless stalagmites and pseudoscorpions waits within one of the world's most beautiful caves.

These millipedes glow not out of attraction, but as a not-too-subtle warning.

The illuminated falls are a gem in North Cascades National Park.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Sunset-colored dunes of volcanic ash make taking a poor photo impossible.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A surreal landscape where fanged rocks rise from the ground and the ocean feels like a great mystery.

A throwback train ride transports passengers through one of the lesser-known national parks in the country.

The fifth-longest natural arch in the world, and the longest outside China.

A glimpse into the lives of the the Miwok and Paiute people in Yosemite National Park.

The remains of an early 1900s dude ranch that operated until the 1970s.

This winding road of 318 curves is a must-visit for (careful) motorcycle and sports car enthusiasts.

No Gordon Lightfoot song, only a barebones monument to greed.

Four hundred granite steps were built into this massive rock by the National Park Service.

The unusual patterns in this rock formation result from two distinct modes of weathering.

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.

Quite simply the largest tree in the world (by volume).

A tiny red pebble marks what may be the quietest outdoor spot in the United States.

A precariously balanced rock perches on the edge of a cliff created tens of thousands of years ago by glacial erosion.

Steep canyon walls hide a forested oasis in the West Texas desert.