Three abandoned missile silos are hiding in plain sight behind a suburban development in Maryland.

This golfball sized platinum iridium cylinder is the official starting point for all national weight calibrations

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

The whole world in one water tank.

This abandoned Victorian-style house was built in 1884.

The largest cemetery for enslaved people in Loudoun County was almost lost to history, if not for the research of a minister.

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.

A terrific purveyor of natural history objects and curios.

Home to items never before seen by the public.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

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

A derelict bit of transportation infrastructure hidden in the woods.

This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.

Bar full of oddities, specimens, artifacts and homages to the great dime museums of the past.

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

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

A Spiritualist house of worship where believers communicate with the dead in the spirit world.

The Byzantine, pre-Columbian, and medieval art at this stately mansion are some of the most under-appreciated collections in D.C.

Obscure Freemasons still live in D.C.’s largest private residence.

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

Giftshop catering to cryptozoologists and anyone with a sense of humor.

Largest Roman Catholic church in North America.

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

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.