Almoloya de Jurez - Seventeen steel doors that only open electronically separate the outside world from prison cell number 20, where Mexican drug lord Joaquin "El Chapo" Guzman lived for 17 months.
But the feared kingpin found another way out: A hole in the floor of his shower that led to a lengthy tunnel built by his henchmen for his weekend bust-out.
The cell of the rich and powerful Sinaloa cartel boss lies at the end of the "special treatments" unit of the Altiplano maximum-security prison 90km west of Mexico City.
On a concrete shelf and small table Guzman left behind a small flat-screen television, leftovers of peanuts and corn tortillas, and a container for stomach-ache medicine, which he took around an hour before his second jailbreak in 14 years.
His is one of only 10 individual cells in the section of the prison reserved for the country's most infamous criminals.
Each of the massive doors that lead to the unit are watched by guards behind a window who only open it once they see an identification.
Authorities allowed reporters and legislators to visit the prison on Wednesday, in what local media dubbed the "Chapotour."
At the top corner of the wall facing cell number 20, a surveillance camera faces the barred door.
Inside, another closed-circuit camera looks into the room, though a blind spot hid Guzman's escape hatch, which leads to the 1.5km tunnel that humiliated President Enrique Pena Nieto's administration.
Before dashing to freedom, Guzman paced in his cell, looked down at the shower floor a couple of times, switched shoes, and crouched down behind a wall before vanishing, according to CCTV footage released by the government.
Authorities suspect that Guzman got inside help and 22 prison officials have been held for questioning since Sunday.
Home to most notorious
Inmates are forbidden from communicating in the special treatments unit. The silence is only broken by the muffled noise of television shows the prisoners watch on their small televisions.
When he escaped, Guzman left his TV lying on a concrete night table, tuned to a popular music show.
The unit's isolated inmates eat in their spartan cells, unlike other prisoners, who have cafeterias.
The Altiplano prison, built 25 years ago, was supposed to be the most secure in Mexico and impossible to break out of.
Guzman had already fooled the authorities once before, in 2001, when he escaped from another prison in western Mexico by hiding in a laundry cart.
Guzman was not the first in his family to be jailed at Altiplano. His brother, Arturo "El Pollo" (The Chicken) Guzman, was murdered in the prison in 2004.
The country's most notorious drug traffickers, kidnappers, murderers and rapists are jailed here.
The prison population includes the previous most-wanted man in Mexico, Knights Templar cartel chief Servando Gomez, alias "La Tuta," who was arrested in February.
It is also home to Hector Beltran Leyva, head of the Beltran Leyva crime family, and a former US-Mexican henchman of the Sinaloa cartel, Edgar Valdez Villarreal, alias "La Barbie."
While Guzman lived in isolation, his signature was among those of 140 inmates who wrote a letter complaining about "inhumane" conditions in March, claiming that there were worms in their food and soiled beds in the rooms for conjugal visits.
While he was complaining about life behind bars, Guzman was plotting his escape, which experts say was likely planned shortly after his February 2014 capture.
His path to freedom ends inside a house built on a property surrounded by fields on a hill.
Guzman used a motorcycle rigged on a rail system to speed through the tunnel.
Two carts are attached to the front of the modified bike.
The tunnel is about 1.7m high and 70cm wide, warm, with a PVC pipe and light bulbs that were blown out.
At the end, he would have climbed a ladder up 12m to an anteroom with a huge, blue generator that powered the tunnel's lights and ventilation system.
A final ladder, with a short 3m climb, led Guzman out of the tunnel and back to being Mexico's most wanted man.