Dr Barnes' $25 billion private collection of art and arboretum.

A decommissioned military complex that's now a modern industrial park.

The only place for a truly presidential dram.

Once forgotten and built over, this historic Black cemetery now houses a poignant memorial.

A former major munitions plant that has been converted into a sprawling art space.

This stately building in Alexandria, Virginia was built by Freemasons to honor one of their most famous members.

This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.

The narrowest house in America is seven feet of pure spite.

The bank that helped fund the Mexican-American War and the purchase of Alaska met its downfall after helping Augusto Pinochet launder money.

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

The grand marble structure next to the White House is Andrew Carnegie's temple to Pan-American diplomacy.

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

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

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

Before Nixon, "watergate" meant canals.

A historic arena where the Beatles played their first concert in the U.S.

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

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

Art deco landmark on the outskirts of Washington, D.C.

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.

Decades before the scandal, this staircase on the river was a literal "water gate."