A super-sized promotional trick that is now a D.C. landmark.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

A much-maligned monument to teetotalism.

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

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

One of the most influential presidents in U.S. history wanted only this plain, elegant monument as his lasting memorial.

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

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

A diminutive plaque recalls the treetop sniper who almost killed Abe Lincoln.

A striking memorial to the 21 lives lost in an explosion at the Washington Arsenal

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

The walls of the iconic dome are hollow and have a secret stairway.

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

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

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.

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

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

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

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

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

The oldest continuously operating fish market in the United States.

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

The United States Capitol's former columns still stand.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.