A surprising, but overlooked example of geology in the middle of the nation’s capital.

A celebrity from the late Cretaceous period.

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

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

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.

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

The tomb was guarded by soldiers from both sides of the war, and some left their initials carved in the brick.

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

Hidden for 165 years inside a building designed by Thomas Jefferson are the remains of what may be America's first educational chemistry lab.

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

Edgar Allan Poe's old dorm is now a shrine to the author's legacy.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

An interesting decoration on this historic site, this weathervane comes with as many legends as it does questions.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

The colonial home of Paul Revere during the American Revolution.

Stolen goods adorn the organ at Old North Church.

The oldest working bell set in North America, the bells at Old North Church sat silent for their first four years in Massachusetts.

The site of Paul Revere's historic two lantern warning.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

In 1958, an MIT fraternity pledge laid down on this bridge and instituted a new, unique unit of measurement.

This bridge was the birthplace of a unit of measurement based on a fraternity joke.

Harry Houdini plunged into the Charles River and performed one of his escape acts here in 1908.

The statue of John Harvard isn't actually John Harvard—or even, technically, the founder of the school.