D.C. once had its own tiny rival to the New York Stock Exchange.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

The ruins of an 18th-century mansion that was once named "Mistake" by the man who had it built.

A mammoth pair of Civil War artillery guns abandoned out in the forest.

The 72-foot giant escaped confinement in a large patch of mulch only to be reburied in the sandy shores of the Potomac River.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

There’s a hidden military meme engraved on the World War II Memorial.

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

This house was once the location of Frelinghuysen University.

The first memorial dedicated solely to the Black troops who fought for the Union.

The final residence of an educator, civil rights leader, and presidential advisor was also the first headquarters of the National Council of Negro Women.

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

Located at the former Lorton Prison the Lucy Burns Museum tells the story of the 91 year history of the prison including the dark chapter of its involvement in the women's suffrage movement.

The first national memorial to honor all women suffragists stands on land where suffragists were once imprisoned.

The last of nine massive kilns that produced many of the red bricks for buildings in Washington, D.C. and northern Virginia in the early 20th century.

These trees are living witnesses to events that inspired poet Walt Whitman’s service during the American Civil War.

Constructed by the younger brother of George Washington.

This war hero's old shop remembers the fine line between medicine and quackery during the Revolutionary War.

A home that witnessed Civil War combat on the Sunken Road has the battle scars to prove it.