Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

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

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

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

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

The home of 1.5 million wood letters for printing is still a functioning workshop.

The oldest university museum west of the Mississippi retains its 19th century feel.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

A museum and shop on Bourbon Street located in the former home of the second Voodoo Queen of New Orleans.

The world’s largest truck stop includes a barber shop, chiropractor, and a huge museum with antique trucks.

Each of these gorgeous, intricately decorated rooms is painstakingly crafted to the scale of 1 inch: 1 foot.

Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

The world's largest military aircraft cemetery.

Experience the hysteria of a 17th century witch hunt through goofy reenactments and wax dummies that should probably be burned at the stake.

When you visit his grave, be sure to rub the Great Emancipator's nose for good luck.

Faceless white figures loom over the city from the rooftop.

These crudely shaped folk giants may be the the second most photographed statues in the U.S.

What's left of the ruins of the 1893 Columbian Exhibition, or World's Fair, also known as the White City.

This historic hotel invented the chocolate brownie.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

A curious fountain that has no water and includes Satan, a crab, and 9 giraffes.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.