The oldest farmer's market in America is so ancient it was approved by the King of England.

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

This English-inspired Maryland garden is home to acres of opulent plant life including bushes shaped into an entire fox hunt.

At this former Prohibition speakeasy, electric birds signaled the arrival of hooch.

Meet some of the most prominent figures in Black history through life-sized wax models.

Once America's tallest structure, now a Baltimore landmark.

One artist’s scheme to expand museum viewing hours into the evening led to the illumination of an entire city.

The trials and tribulations of marking Poe’s grave.

Baltimore's classic clock tower was once topped by a rotating, 20-ton medicine bottle.

A museum dedicated to exhibiting remarkable outsider art.

This bridge over D.C.'s Rock Creek Park is sometimes called the "Buffalo Bridge" because of its four buffalo sculptures, which were cast from a single piece of bronze.

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

The national park was once a plantation estate.

After James Madison's death, his wife and former First Lady Dolley Madison lived in this yellow building near the White House.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

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

The "lovely red Vega" of the legendary record-settling pilot.

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.

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

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.