Native Americans built this circle of stones, which was used to predict astronomical events.

An unusual geological feature towers over the remains of a dark episode in United States history.

At the time of its completion, it was the tallest dam in the world.

One man's ambition created this psychedelic log home.

The mayor made the declaration in 2004.

This oddity shop contains everything from antique tools to a human skeleton.

After this former brothel closed, its interior remained almost frozen in time.

A mining town, now abandoned, was built in a canyon so narrow that the railroad ran right through the hotel lobby.

This landmark is a central figure in the Nez Perce origin story.

This playground sculpture of an icon from the past is dedicated to the children of the future.

Local legend has it that an old, decaying staircase outside this cemetery is haunted by dozens of ghosts.

This shallow pit was once used to send over 20,000 buffalo plummeting to their death.

The crumbling structure is a rare surviving relic of the area's bygone mining industry.

The first declared National Monument in the United States.

This beautiful ancient site is dotted with perforated sandstone pillars considered sacred by some Native American groups.

This record-setting hydraulic dam in the Montana badlands was one of FDR's most ambitious public works.

The ruins of Theodore Roosevelt's beloved ranch stand in a forgotten corner of a national park named after him.

This erect, phallic geological spire wasn't always named so domestically.

The world's largest Holstein cow.

The final resting place of the Hunkpapa Lakota leader Tatanka Iyotaka, commonly known by the English translation Sitting Bull.

A monument to the forgotten French explorers and their landmark expedition.

A striking sculpture built to honor the women of the Lakota and Dakota Nations.

Today this bizarre rooftop phone booth seems like a piece of kitsch but it was once used to spot disastrous storms.

The world's largest covered wagon is piloted by a giant Lincoln lawyer.