The iconic D.C. restaurant where the Cuban Missile Crisis was negotiated, now a Walgreens.

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.

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

The national park was once a plantation estate.

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

There’s a hidden military meme engraved on the World War II Memorial.

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

The most accurate timepiece in the world.

The privately owned cemetery that holds room for Washington's finest when they step down from life.

A lovely aquatic park built by a one-armed Civil War veteran who made a fortune from lotuses.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

The site of the climactic scene from the classic horror film is now a historic landmark.

The United States Capitol's former columns still stand.

A clear example of the process of erosion in action.

Nine limestone rock stacks on Australia's "Shipwreck Coast."

A small, but award-winning beach known for its literally spotless reputation.

Herbert Hoover's "Brown House" rural presidential retreat was a PR disaster amid the start of the Great Depression.

The romance of early commercial flight still fills this Art Deco destination.

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

Rumor has it the hot dog stand was targeted by two Russian nuclear missiles.

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

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

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.