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

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

This ruined quarry once produced the distinctive red sandstone used for construction projects in Washington, D.C.

Maryland's first (and last standing) toll house on America's first federal road established the state as the "Gateway to the West."

An eerie, abandoned military base engulfed by nature and graffiti is now home to a local park.

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

This one-room cabin where the young colonel slept during the French and Indian War.

Politicians, bureaucrats, and military officers gathered in this field near the Capitol to settle their disputes with blood.

This beautiful stone arch bridge wasn't even expected to stand for one day, but people have been crossing it for centuries.

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.

This former asylum for Black Americans is haunted by its history of violence and racism.

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

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

The 320-year-old tree that greeted General Lafayette and rerouted an interstate highway.

Ship skeletons haunt Baltimore's waterways.

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

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

An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.

The ruins of this long-abandoned unsuccessful gold mine can still be found.

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.

Remnants of a storybook amusement park hidden behind a strip mall.

The shelves in the back of this thrift store are devoted to saving, not selling, retro tech.

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