The tallest The Church of Jesus Christ of Latter-day Saints temple in the world soars above the Beltway.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

There’s a special club house at the top for the bell ringers.

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

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

The most accurate timepiece in the world.

A wondrous old library overlooking the nation's capital.

Parking garage where Bob Woodward met Watergate source "Deep Throat."

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

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

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

The Byzantine, pre-Columbian, and medieval art at this stately mansion are some of the most under-appreciated collections in D.C.

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

The national park was once a plantation estate.

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

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.

Decades before the scandal, this staircase on the river was a literal "water gate."

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

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

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