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

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

Both the building and blades of this reconstructed 19th-century windmill can turn in a breeze.

The United States' oldest Episcopal church still in active use.

An isolated island home to one of the oldest English-speaking communities in the region and Maryland's state dessert.

This scenic Maryland park was the site of one of the worst prison camps of the Civil War.

The 72-foot giant escaped confinement in a large patch of mulch only to be reburied in the sandy shores of the Potomac River.

Remains of a historic fountain that was mysteriously lost in the demolition of a D.C. traffic circle.

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

One of the earliest and best-preserved buildings in Charles County, Maryland.

The remnants of a wooden-hulled fleet built and abandoned in WWI, now home to a thriving ecosystem.

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

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

Bizarre Cavern.

Unannounced visitors are now welcome at the site of the largest Prohibition-era bootlegging operation in the region.

An eerie, decaying ghost town destined to fade into the forest.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

A local farm's collection of unusual structures from a now defunct storybook amusement park.

This dig site outside D.C. is known for its exceptionally high density of baby dinosaur fossils and dinosaur eggs.

Hidden within an idyllic suburban garden is a memorial dedicated to the victims of a terrifying spree of killings committed on U.S. soil.

The headquarters of the Audubon Naturalist Society is a small slice of heaven for nature lovers.

This propitious plastic porcine has been petitioning park visitors to pick up after themselves for more than 50 years.