Berkeley Springs State Park boasts the nation's only monument commemorating presidential bathing.

A star fort along the C&O Canal in western Maryland that protected America in three wars.

An almost life-sized elephant named Ms. Ellie greets visitors at this jumbo-themed museum.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

A monument marks the location of the first successful steamboat demonstration.

A pre-Industrial Age iron furnace and the site of a nearly-forgotten piece of Black history.

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

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

This grave marks the passing of a historic Jane Doe whose identity remains a mystery to this day.

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

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

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

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

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.

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

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

This Virginia railway overpass is said to be haunted by a serial killer in a rabbit costume.

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

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

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

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

A much-maligned monument to teetotalism.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.