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

The oldest continuously operating fish market in the United States.

A museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

A wondrous old library overlooking the nation's capital.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

The site of the climactic scene from the classic horror film is now a historic landmark.

Once the center of a thriving early Black community called Martinsburg.

The only public school for Black children in the region from 1895-1936.

The hidden ruins of a mill that is linked to an attempt to assassinate the vice president of the United States.

One of only two sites in the United States containing the remains of Buddha.

Built in 1815, the stabilized ruins of the grist mill and sawmill are now gated, but interpretive displays on the features and functions of the mill preserve its history.

The privately owned cemetery that holds room for Washington's finest when they step down from life.

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

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

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.

The discovery site of the "Capitalsaurus," the official dinosaur of Washington, D.C.

The Corinthian columns that towered over Abraham Lincoln’s inauguration stand proud.

A derelict bit of transportation infrastructure hidden in the woods.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

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

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

This taxidermy horse was a Civil War hero.

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

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