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

Rippling sand dunes frozen in the Arizona rock.

This ancient cave is home to a museum, bar, and is filled with fluorescent minerals.

This set of three large, volcanic hot springs is a favorite haunt for intrepid divers.

A tunnel with windows, so you don't miss out on the impressive views.

A Mars simulation in the southern Utah desert.

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

One man has installed bathtubs into the Utah desert floor to harness the powers of a natural hot spring.

This geothermal hot spring hides beneath a slowly growing mineral dome.

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.

Here, at the "world's longest art gallery," you'll find forty miles of ancient petroglyphs and pictographs.

A devilishly named gorge that was a sign of salvation for many pioneers.

This UFO landing strip was created by a charitable Wyoming city that was worried about residents of Jupiter.

This prison-turned-museum is a remnant of the Old West's grizzly, violent past.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

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

The first declared National Monument in the United States.

A beautiful geyser under environmental threat.

A classic mystery spot complete with spots that are said to make you shrink or grow when you stand on them.

A little-visited ghost town state park offers a glimpse into Montana’s "Silver Queen."

This off-the-beaten-path abandoned town is a relic of Montana's silver mining boom.

The rocks of a certain area of Butte, Montana give off a musical ring when hit.

New fungal and bacterial species call this deadly lake home.

Non-profit time travel mart sells goods you would need for a trip through the fourth dimension.