An architect's childhood fantasy treehouse made real.

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.

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

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

A beautiful geyser under environmental threat.

The first declared National Monument in the United States.

Despite repeated attempts to make it work, this former mining town is now nothing but dust and memories.

One devoted couple has donated multiple recreations of Michelangelo's sculptures to this South Dakota town.

A fitting attraction for the corn capital of the world.

This prehistoric sinkhole lured exclusively male mammoths to their death, much to the delight of science.

Hidden behind Lincoln's head is a 70-foot-long chamber containing enamel plates documenting American history, sealed in a teakwood box in a titanium vault.

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