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

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

One of the oldest active carousels in the country—but it might be missed by all but the keenest-eyed boardwalk strollers.

This advertisement for talcum powder was painted on the rock face and has since defied removal.

She stares out across six lanes of traffic, clutching a musket and infant with determination.

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.

This historic lighthouse was well known for the large number of women who served as its keeper.

Home of the physician who set the leg of John Wilkes Booth after the Lincoln assassination.

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

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

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

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

The whole world in one water tank.

Built by the patriotic residents of Boonsboro in a single day.

A cave on the Maryland border where civilians took refuge during the bloodiest battle of the Civil War.

Despite violent work crews and massive delays this abandoned canal tunnel was built to last into the modern day.

The land is home to swimming ponies and a legendary 18th-century treasure.

Bizarre Cavern.

The trials and tribulations of marking Poe's grave.

A labor of love built by local hang-gliding enthusiasts, this ideal launch spot was outlawed by the authorities and has since been largely abandoned.

The Cold War-era "underground Pentagon" is a sprawling subterranean hideaway for the Defense Department.

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

The bridge's highly-contested plaque (once again) honors Confederate President Jefferson Davis.