The U.S. Navy’s preposterously detailed mini battleship took 77,000 hours to complete.

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

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

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

A much-maligned monument to teetotalism.

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

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

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

The national park was once a plantation estate.

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.

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

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

Before Nixon, "watergate" meant canals.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

The "lovely red Vega" of the legendary record-settling pilot.

Home to items never before seen by the public.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

FDR's Art Deco hospital tower was hopelessly inefficient.

The largest clock face in the United States is twice the size of Big Ben and infinitely more ad-sponsored.

The United States’s oldest funicular railway glides up and down a steep Pittsburgh street.

Color-coded signs direct drivers on a network of routes designed to avoid Pittsburgh traffic.

This replica of the Greek structure is in the heart of Nashville.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

At 207 feet, one of the world's longest continuous escalators.