There's a crumbling old mansion inside the Smithsonian National Zoo.

The naval commander’s proudest moment in battle is memorialized in this unique tomb at Arlington Cemetery.

The rogue roots are gradually consuming some of the historic marble grave markers.

Perhaps the most scandalous statue of America's first president.

Please don’t anchor your boat onto the Department of Defense’s underwater data cables.

This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.

Outposts of this restaurant chain were shaped like jaunty chapeaus.

These unusual rooms on wheels are holdovers from the 1960s.

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

A Bhutanese temple gifted from the isolated Himalayan kingdom is now a surprising cultural gem located at the University of Texas at El Paso.

This southwest-styled home in Santa Fe claims to be the oldest house in America thanks to an ancient bit of foundation.

This innocuous New Mexico storefront was once the secret jump-off spot for Manhattan Project scientists.

Rhode Island's tallest building bears a resemblance to the "Daily Planet" building and has been empty for more than five years.

What is the Thing?

Public works and national defense project meant to carve a canal all the way across the state of Florida.

Legend says train robbers stashed their gold within the depths of this unusual cave.

This Boeing KC-97 tanker is now a restaurant for aviation lovers.

At 207 feet, one of the world's longest continuous escalators.

This Chinese-style quartz sundial was saved in its final hour.

FDR's Art Deco hospital tower was hopelessly inefficient.

Look closely and you’ll notice that the color changes a third of the way up the tower.

The romance of early commercial flight still fills this Art Deco destination.

One of the world's largest tanks mimics the experience of watching rare whale sharks, giant rays, and deep sea creatures from the ocean floor.