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

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

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

A painfully obvious spy house sits right across the street from the Russian Embassy.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

This grand gothic brewery has been pumping out suds for over a hundred years.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

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

Home to items never before seen by the public.

An oft-overlooked, magically musical monolith that stands majestically between Arlington Cemetery and the Iwo Jima Memorial.

This train station inspired the name of a 1970's rock band and provided the backdrop for their album cover.

A superbly preserved example of Georgian residential architecture that was once home to one of the founders of Alexandria, Virginia.

The most historic church in Fairfax County played a role in the creation of the American Red Cross.

The Pentagon sits on a former island that was in Virginia at low tide and D.C. at high tide.

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

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

The controversial urban planner who designed Washington, D.C., was buried in Maryland, and can presently be found in Virginia.

This pun was simply waiting to come to life, and one defense contractor made it so.

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

The final resting place of an unidentified revolutionary soldier sits behind a Virginia church.

The story behind the mysterious symbol painted in front of the historic university's famous Rotunda.

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

The remains of a historic plantation nestled in between a parking lot and the rental car return at Reagan National Airport.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.