This cannon dating to 1755 has stood guard at this suburban intersection since 1915.

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

This pharmacist and his patient greet visitors to the National Community Pharmacists Association.

Once the largest trading firm of enslaved people in the U.S., this building is now a museum that preserves Alexandria's dark past.

The narrowest house in America is seven feet of pure spite.

A massive, majestic mammal watches over pedestrians from his perch atop a former B.P.O.E. lodge.

This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.

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

The ruins of an 18th-century mansion that was once named "Mistake" by the man who had it built.

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

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

One of the most influential presidents in U.S. history wanted only this plain, elegant monument as his lasting memorial.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

This unassuming passageway played a key role in one of the most important events in U.S. history.

The bank that helped fund the Mexican-American War and the purchase of Alaska met its downfall after helping Augusto Pinochet launder money.

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

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

This robust fence in front of a historic Georgetown home is likely made from hundreds of recycled Revolutionary War firearms.

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.

This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.

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

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

The tallest The Church of Jesus Christ of Latter-day Saints temple in the world soars above the Beltway.