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.

The 72-foot giant escaped confinement in a large patch of mulch only to be reburied in the sandy shores of the Potomac River.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

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

This sprawling farm was once a Cold War-era hideaway for the nation's top diplomats.

America's post-nuclear-attack chambers of Congress.

This beautiful vintage movie palace has seen little change in form or function since the 1920s.

The only recreation of William Shakespeare's indoor playhouse.

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

An abandoned textile mill that is now home to art and concerts.

Thomas Jefferson's estate is home to hundreds of varieties of historic fruits and vegetables.

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

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

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

An eponymous directional signpost erected by the first president of the United States.