A building shaped like the Army Corps of Engineers logo, because why not?

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

A line of blue paint marks the route of the inaugural parade.

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

The national park was once a plantation estate.

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

Every drop of D.C. tap water flows through this old waterworks.

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

They sort through millions of dollars worth of diplomatic gifts on behalf of the government.

The oldest continuously operating fish market in the United States.

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.

This poor little statue is the most vandalized memorial in Washington.

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

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.

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

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

Light bulbs, scrap wood, and tinfoil comprise this homemade throne of the gods.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

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

Largest Roman Catholic church in North America.

This imposing Masonic temple a mile from the White House was the first public library in Washington, D.C.

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.