This nine-story building is the oldest standing skyscraper in D.C.

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

Go take a picture with the inventor of the daguerreotype photographic process.

This poor little statue is the most vandalized memorial in Washington.

An unassuming, powerful monument north of the U.S. Capitol bears witness to the resilience of Japanese Americans during a time of grave injustice.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

It was once the base for a series of domestic terror attacks.

A nostalgic bibliographic gem.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

The world's largest Holstein cow.

One man's quest to save his town with a trail of record-breaking sculptures.

This simple badlands butte is the highest point in North Dakota and may be the only high point to charge admission.

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

Thanks to a loophole in property ownership, this alleyway has become a cacophonous street gallery.

The first declared National Monument in the United States.

A cemetery housing wild west legends in South Dakota.

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

Yes, this monument is aware that it is about 20 miles away from the actual center of the United States.

One of America's first dinosaur parks gives a window into Depression-era paleontology.

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

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

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.