A spectacular tribute to statesman and philanthropist Andrew Mellon.

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

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

A tribute to the pop culture icon overlooks this Washington D.C. intersection.

There’s a special club house at the top for the bell ringers.

Where you can hail your favorite fictional commanders-in-chief.

The most accurate timepiece in the world.

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

This forlorn park is the result of a failed investment turned tax dodge.

A human attendant once directed car traffic from this structure before automated stoplights.

One of America's first spies started out as a teacher in this little red one-room schoolhouse.

A failed piece of Orientalism has become the proud symbol of a community.

A priceless collection of the Nation's cryptologic history.

One of the U.S. Forest Service's only mansions is outfitted with a dinner table for floating food.

Mysterious rocks that ring musically when struck.

This beloved marketplace mascot poops money and grants good luck.

South Philadelphia is home to Keith Haring's only surviving in situ collaborative public mural.

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

This large garden vase urn has nothing to do with the seventh U.S. President—it was designed by one landscape designer to honor another landscape designer's contributions to the National Mall.

Helen Keller once broke ground on this historic center for the study of technologies to benefit the hearing impaired.

The fountains of the U.S. Navy Memorial are annually salted with water from the Seven Seas as part of a nautical ritual.

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

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.