Built to defend Washington D.C. during the Civil War, this fort became a post-war nucleus for a thriving Black community.

These unusual rooms on wheels are holdovers from the 1960s.

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

Before founding the American Red Cross, Clara Barton had a tremendous humanitarian impact by locating thousands of missing soldiers.

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

A small but charming botanical garden that contains many exotic plant species.

This historic streetcar system has been running since the 19th-century.

A hidden three-foot-wide house separates these two regal churches.

Elaborate tile work in this railway station tells the story of Portugal.

Ancient catacombs form the foundation for this Rococo orgy of a church.

The stunning interior of this Gothic church is covered in ornate gold details.

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