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.

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

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

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

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

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

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

A heroic pigeon that, through a barrage of gunfire, delivered a message that saved over 100 lives in World War I.

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

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

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

The most accurate timepiece in the world.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

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

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

The most decorated dog of World War I is preserved in the Smithsonian.

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

After the famous composer died in Paris, his sister snuck his heart out of the country to honor his wish that it be buried in their native country.

A program of Communist glamour in post-Stalin Poland is preserved in this colorful museum.

A 20th-century picture show in 3-D.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

Fittingly, America's museum of architecture is itself a magnificently designed old building.