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

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

A roadside collection of over-sized iron creations that are a bit more macabre than most.

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

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.

Just a man taking his prehistoric pet for a stroll.

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

A place where the laws of nature seem to have gone completely berserk... but of course haven't.

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

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

A super-sized promotional trick that is now a D.C. landmark.

Largest Roman Catholic church in North America.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

The United States Capitol's former columns still stand.