It's not hard to see why the historic Peabody Conservatory of Music's library has been described as a "cathedral of books."

A star-shaped fortress town fort built in the geometric model of the Renaissance utopian city.

The world's first hotel built in an abandoned water-filled quarry.

A quaint amusement park now sits, rusting and forgotten among the foliage.

Two ancient Buddhist temples crown this dramatic rocky pinnacle.

A submerged archeological park still holds the wonders of a Roman Sodom.

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

A historic ruin just 20 feet away from a busy highway onramp.

Once the supplier for noteworthy projects like the National Cathedral, this old brickworks now lies abandoned.

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

Cold War intelligence agents monitored communist embassies from an attic in a former pigeon coop.

An Industrial Revolution-era public work that purified water using nothing but sand.

People escaping slavery may have hidden inside a corpse vault.

Helen Keller once broke ground on this historic center for the study of technologies to benefit the hearing impaired.

A building shaped like the Army Corps of Engineers logo, because why not?

An obscure federal monument honors the French diplomat who served as Ambassador to the U.S. during WWI.

The innocent intentions of this monument are somewhat lost in the sculpture's muscled imagery.

An overlooked tribute to one of the most important peace deals in American history.

The iconic D.C. restaurant where the Cuban Missile Crisis was negotiated, now a Walgreens.

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

Also known as the Founding Church of Scientology.