Holmesburg Prison, Former prison in Philadelphia, Pennsylvania, United States

Holmesburg Prison is a former correctional facility in Philadelphia designed with a spoke-and-wheel layout where multiple cell blocks radiate from a central observation point. The structure reflects late 19th-century prison architecture and the security approaches that defined institutional design during that era.

The facility was established in 1896 to relieve overcrowding at Moyamensing Prison and operated until 1995. Over that century of use, it experienced multiple riots and violent incidents reflecting the institutional strain of the era.

The site represents a turning point in how society views medical ethics and prisoner rights. Visitors often reflect on the human suffering that occurred within these walls and what it means for modern medical standards.

The site now serves as a training location for law enforcement and emergency response personnel and occasionally functions as a filming location. Visitors should check access policies beforehand since the facility remains an active training ground with limited public availability.

Between 1951 and 1974, a dermatologist conducted hundreds of chemical and pharmaceutical experiments on inmates here, including tests with radioactive materials. These tests occurred without consent and represent one of the darkest chapters in medical research history.