The final resting place of two (or three) presidents, one vampire, and 18,000 Confederate soldiers.

An alternate history park where the Union Army loses the war... to dinosaurs.

The skeletal white beams stand as a monument to religious dissent.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

Heron, whitewater rapids, and urban industrialism all add to the beauty of this concrete nature walk.

This 29-ton granite ball spins around at the slightest touch thanks to a scientific phenomenon.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.

Outsider art meets paleontology at this roadside reptile repository.

This museum devoted to the gothic author holds such interesting ephemera as his socks and walking stick.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

Giant busts of 42 U.S. presidents are sitting in a field in Virginia.

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

This bridge over D.C.'s Rock Creek Park is sometimes called the "Buffalo Bridge" because of its four buffalo sculptures, which were cast from a single piece of bronze.

The story behind this beloved toy—named for Theodore Roosevelt and owned by his grandson—is more complicated than you might guess.

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

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

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.

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

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

An overlooked memorial honoring the local Washington residents who died in World War I.

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

Washington's iconic carousel has a nice piece of Civil Rights history.

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

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.