This isn't your average roadway—it's actually a National Park and a transportation pioneer.

Washington's top-secret Cold War-era doomsday communications tower is located in a small neighborhood park.

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

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

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

Before founding the American Red Cross, Clara Barton had a tremendous humanitarian impact by locating thousands of missing soldiers.

An amazing example of early-20th-century architecture, this church features marble transported from Utah.

This imposing Masonic temple a mile from the White House was the first public library in Washington, D.C.

A clone of a cloned tree that was so important it allegedly had its own guards.

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