Take a drunken tour inside the world's largest known geode.

This taxidermy horse was a Civil War hero.

The 28,000-year-old specimen is remarkably intact.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

A line of blue paint marks the route of the inaugural parade.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

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

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

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

Washington's iconic carousel has a nice piece of Civil Rights history.

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

The "lovely red Vega" of the legendary record-settling pilot.

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

The most decorated dog of World War I is preserved in the Smithsonian.

There’s a hidden military meme engraved on the World War II Memorial.

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

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

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

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

Home to items never before seen by the public.

Once decrepit and slated for demolition, now one of the longest pedestrian bridges in the world.

More than five miles of underground passageways.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

There's something big lurking beneath the surface of this tiny Oregon park.