A tour group wanders through block 7 of Eastern State Penitentiary in Philadelphia, Pennsylvania April 30, 2014. Opened in 1829, with the original corrective system of “confinement in solitude with labor”, the penitentiary housed about 75,000 inmates in its 142 years of operation. At Eastern State reunions, former inmates, staff and guard gather to share memories and trade stories and get a chance to describe their experiences in question-and-answer sessions with the public. (Photo by Mark Makela/Reuters)

A visitor wanders through block 7 of Eastern State Penitentiary in Philadelphia, Pennsylvania April 30, 2014. (Photo by Mark Makela/Reuters)

The entrance to block 9 is seen at the now-closed Eastern State Penitentiary in Philadelphia, Pennsylvania April 30, 2014. (Photo by Mark Makela/Reuters)

Rain falls onto block 14 of Eastern State Penitentiary in Philadelphia, Pennsylvania April 30, 2014. (Photo by Mark Makela/Reuters)

The Eastern State Penitentiary central observation tower is seen in Philadelphia, Pennsylvania April 30, 2014. (Photo by Mark Makela/Reuters)

A visitor speaks on the phone in the south corridor of the closed Eastern State Penitentiary in Philadelphia, Pennsylvania April 30, 2014. (Photo by Mark Makela/Reuters)

Crumbling cell blocks in Eastern State Penitentiary are seen from the central observation tower in Philadelphia, Pennsylvania April 30, 2014. (Photo by Mark Makela/Reuters)

Former inmate at Eastern State Penitentiary, William Harrison, 75, served 3 separate terms (1959, 1962, 1970) for larceny, forgery, and assault, and revisits his prison cell on the second level of block 14 in Philadelphia, Pennsylvania April 30, 2014. (Photo by Mark Makela/Reuters)

The Eastern State Penitentiary gatehouse as viewed from the second level, in Philadelphia, Pennsylvania April 30, 2014. (Photo by Mark Makela/Reuters)

A cut-out prison guard silhouette with flashlight, part of a current exhibition at Eastern State Penitentiary, stands in the grounds in Philadelphia, Pennsylvania April 30, 2014. (Photo by Mark Makela/Reuters)

Window light illuminates the remains of a cell in block 14 of Eastern State Penitentiary in Philadelphia, Pennsylvania April 30, 2014. (Photo by Mark Makela/Reuters)

A painting of the Virgin Mary and child remains in the radio room of the now-closed Eastern State Penitentiary in Philadelphia, Pennsylvania April 30, 2014. (Photo by Mark Makela/Reuters)