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

This brick-lined pedestrian walkway was once a railway tunnel used during the Civil War.

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

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

The historic home of an educator, abolitionist, activist, and poet.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

Built in the 1850s, this church was of the first five churches constructed in Harper's Ferry.

This shale formation along the Appalachian Trail once inspired the third president of the United States.

One of the only memorials dedicated to journalists who died in combat.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

The first memorial dedicated solely to the Black troops who fought for the Union.

The world's oldest soul food restaurant is also one of its best.

Cold War intelligence agents monitored communist embassies from an attic in a former pigeon coop.

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

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

Largest Roman Catholic church in North America.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

The United States Capitol's former columns still stand.

Brain collection and database that narrows the gap between man and animal.

An astounding collection of medical specimens, including bits of President Lincoln.

A Civil War fort in the middle of Washington, D.C. has been swallowed by a forest.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

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