The final resting place of an unidentified revolutionary soldier sits behind a Virginia church.

A massive, majestic mammal watches over pedestrians from his perch atop a former B.P.O.E. lodge.

A former major munitions plant that has been converted into a sprawling art space.

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 super-sized promotional trick that is now a D.C. landmark.

The United States Capitol's former columns still stand.

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

Outside the Department of Transportation, a collection of artifacts honors the history of how we get around.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

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.

A historic neighborhood church is reborn as a psychedelic arts collective.

Art deco landmark on the outskirts of Washington, D.C.

A painfully obvious spy house sits right across the street from the Russian Embassy.

The oldest continuously operating fish market in the United States.

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

The national park was once a plantation estate.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

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

The most accurate timepiece in the world.

Home to items never before seen by the public.

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