This lovely pocket park is one of the most under appreciated in D.C.

The oldest continuously operating fish market in the United States.

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

Go take a picture with the inventor of the daguerreotype photographic process.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

A whopping 14,000 copper coins cover this miniature fighter jet.

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

This pharmacist and his patient greet visitors to the National Community Pharmacists Association.

The narrowest house in America is seven feet of pure spite.

This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.

This small pedestal marks the spot of the first lot of land sold in Alexandria, Virginia in 1749.

America's first federal monument.

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

A much-maligned monument to teetotalism.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

An echo chamber with a waterfall wrapped around its base at the Embassy of Canada in Washington, D.C.

A spectacular tribute to statesman and philanthropist Andrew Mellon.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

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

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.

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

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

On the Fourth of July this area will transform into a Pompeii-like storm of falling embers and ash.