This is an empty field in Bensalem, a neighborhood in Philadelphia, Pennsylvania. There’s not much to see here now, and that’s very much by design. From 1907 to 2006 the Byberry Mental Hospital (also known as the Philadelphia State Hospital at Byberry) stood here. Infamous for its harsh conditions, shocking neglect and incomprehensible human rights violations, during the 80 years the hospital was open it was easily one of the most hellish and terrifying places in the United States.

The story of Byberry is uniformly sad and outrageous. Established in an age when mental illness was poorly understood, its administrators and doctors surely meant well, but the place was overcrowded, understaffed and too few people cared much about the mentally ill patients who were sent here, often to live out their lives. Sanitary conditions were disgusting; there were frequent reports of excrement fouling corridors and patients lying for days in urine-soaked beds. Beatings and sexual abuse by sadistic employees added to the problem. In 1945 a conscientious objector sent to the hospital smuggled out pictures of the place, which resembled Nazi concentration camps. The photos created a national uproar, but even that didn’t redeem Byberry. A series of investigative reports in the late 1960s documented that it was still a hell-hole. Even then it took over 20 years to close the place down. Its final patients were transferred out in June 1990.

Even after its closure the spell of Byberry’s horror remained. Now an abandoned complex of decaying buildings, empty of patients the hospital was almost as frightening as it was when it was still operating. Urban explorers roamed its halls and covered every wall with graffiti. Haunting photos of Byberry in this period are still up on urban exploration sites, such as Opacity. Warning: while eerily beautiful, the photos will creep you out.

State authorities, frustrated by the place’s lingering reputation and the attraction it held for vandals, finally bulldozed the place in 2006. Since then it has been like you see it above–an empty field of flowers and shrubs, but still under the shadow of the madness and horror that happened here.