The grounds of former plantations where abolitionist Harriet Tubman spent her youth enslaved are now a museum to her incredible life.

The "Sultan of Swat" once attended a school at the site of this baseball field.

The oldest military monument in the United States.

Just outside the Naval Academy, Hell Point is a historical marker that could easily be the point where failed students wait for the bus.

One of the largest collections of Catalan literature and cultural materials outside of Spain, created by a community of 1960s expats.

A state park that once served as an important river crossing, and now offers protected lands for endangered plants and animals.

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

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

A relic of FDR's brief foray into utopian urban planning.

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

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

The development and impact of electronic media showcased in a picturesque farmhouse in Maryland.

The world's oldest continuously operating airport was founded by the Wright Brothers.

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

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

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

The longest escalator in the Western Hemisphere takes over three minutes to ride down.

Captain John Smith thought these cliffs were amazing in 1608 but sharks thought so 20 million years before him.

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

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

A priceless collection of the Nation's cryptologic history.