Sing Sing Penitentiary opened in 1826 to serve New York City’s growing population and crime rate, and was known in its early days for its stringent code of conduct. In the prison’s early days, warden Elam Lynds invented the lockstep style of moving inmates in closely interlinked lines, as well as the striped inmate uniforms used for easy identification — both of which would come to define the popular view of prison aesthetics for centuries.