The last masonry skyscraper ever built reveals a transitional moment in architectural history.

A spectacular remnant of an Adler and Sullivan masterpiece that was destroyed in 1972.

To find the "unicorns of the deep" you've got to go downstairs.

In the Shawnee National Forest, amazing rock formations peer through the treeline.

River pirates, murderous bandits, and serial killers used this Illinois cave as their debauched hideout.

This rare vessel mixed luxury with labor before being converted to a museum and sometimes haunted maze.

This picturesque cliffside beacon no longer calls to sailors but shines once a year in honor of a famous shipwreck.

At this Minnesota state park you can easily wade across the source of the mighty Mississippi.

Half of a waterfall goes into the river while the other half seems to disappear.

A legal loophole makes it possible to get away with murder within this 50-square-mile section of Yellowstone.

Spectacular views await visitors to this lake.

An apocalyptic seismic event creates a deadly chain reaction that ends with a 6-mile long lake developing within weeks.

Dedicated to the history of the 1,000 nuclear missiles that once covered the Great Plains.

Every president in history is immortalized in bronze in downtown Rapid City.

South Dakota's oldest operating brewery is housed inside a historic firehouse.

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

This replica stave church looks like a piece of Norway was simply plopped down in South Dakota.

One of America’s oldest and spookiest hotels, thanks to the residency of ghosts, dead presidents, and Alfred Hitchcock.

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

This rustic old building is said to be the most photographed barn in America.

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

One man's ambition created this psychedelic log home.

An architect's childhood fantasy treehouse made real.

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