It was once the base for a series of domestic terror attacks.

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.

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.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

The innocent intentions of this monument are somewhat lost in the sculpture's muscled imagery.

Through the decades, Black music stars have performed at this historic hub for music and the arts.

The world's oldest soul food restaurant is also one of its best.

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

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

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

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

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

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

A much-maligned monument to teetotalism.

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

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

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

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

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

A clone of a cloned tree that was so important it allegedly had its own guards.

Perhaps the most scandalous statue of America's first president.

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

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.