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

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

A lovely aquatic park built by a one-armed Civil War veteran who made a fortune from lotuses.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

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

This grand gothic brewery has been pumping out suds for over a hundred years.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

Rumor has it the hot dog stand was targeted by two Russian nuclear missiles.

Taste the white whiskey that the United States' first president once distilled and enjoyed.

A gift from Scotland to the United States in memory of the 270 lives lost when Pan Am Flight 103 exploded over Lockerbie due to a terrorist bombing.

Though his role as the inventor of baseball may be up for debate, fans still festoon Doubleday's grave with baseballs.

The former home of Thomson Francis Mason, the mayor of Alexandria from 1827-1830.

In what is rumored to be an intentional act of spite, this memorial almost completely obscures the nearby grave of a senior officer.

This cannon dating to 1755 has stood guard at this suburban intersection since 1915.

The only remaining African American schoolhouse in northern Virginia is now a museum dedicated to formerly enslaved people.

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

The system of air guns are fired off remotely to scare any trespassing avians.

The Pentagon sits on a former island that was in Virginia at low tide and D.C. at high tide.

Born a slave on the Arlington estate, Parks dug the first graves at Arlington National Cemetery, and was buried there, too.

These figures float and flutter in this fountain crafted by famed Swedish sculptor Carl Milles.

Please don’t anchor your boat onto the Department of Defense’s underwater data cables.

This historic, one-acre island is the only legal place to camp in the city of Richmond.

The Kirkland Monument remembers a selfless Civil War hero who braved the battlefield to give water to his dying enemies.