19°25′14″N 99°44′55″W / 19.42056°N 99.74861°W
The Federal Social Readaptation Center No. 1 "Altiplano" (Spanish: Centro Federal de Readaptación Social Número 1 "Altiplano") is a maximum security federal prison of the Secretariat of Public Security in Mexico. It was originally called the Penal de Máxima Seguridad No. 1 "Almoloya de Juárez", later renamed the Federal Social Readaptation Center No. 1 "La Palma"[1] (Centro Federal de Readaptación Social No. 1 "La Palma"), before assuming its present name. This facility is located in the Santa Juana Centro neighborhood of Almoloya de Juárez, in the State of Mexico,[2] 25 kilometers (16 mi) from Toluca.[3]
The prison was built between 1988 and 1990 under President Carlos Salinas de Gortari and received its first inmates in November 1991.[4][5] Of significant concern to Mexican authorities is the risk that the prison could be attacked from the outside as part of an organized prison break.[6] Therefore, the walls have been reinforced to as much as 1 meter (3.3 ft) in thickness to discourage ramming. Furthermore, the air space near the facility is restricted, and the authorities claim that cell phone transmissions are limited within 10 km (6.2 mi) of the prison to stymie communications between the inmates and their colleagues outside. Additionally, armored personnel carriers are based near the facility to protect it during a potential assault. This prison was thought to be impenetrable until July 11, 2015, when Joaquín "El Chapo" Guzmán escaped through a tunnel.