Mexico's infamous prison cell, scene of Guzman's escape

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 purpose-built 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 90 kilometers (55 miles) west of Mexico City.

On a concrete shelf and small table, Guzman left behind a compact 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 1.5 kilometer (one-mile) 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 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.

A former inmate of the special cell block, Flavio Sosa, told AFP that it was surprising that a tunnel could have been built without anybody hearing any noise.

"You could hear your neighbor snoring, the guard walking, noise from another hallway," said Sosa, jailed in cell number 13 for 10 months in 2006-2007 on sedition charges after leading protests, before being acquitted.

"Silence reigns in this prison. Any noise that breaks the silence is noticeable."

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, including Knights Templar cartel chief Servando "La Tuta" Gomez.

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.

- Motorcycle escape -

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 1.7 meters (5.5 feet) high and 70 centimeters wide, warm, with a PVC pipe and light bulbs that were blown out.

At the end, he would have climbed a ladder up 12 meters to an anteroom with a huge, blue generator that powered the tunnel's lights and ventilation system.

A final ladder, with a short three-meter climb, led Guzman out of the tunnel and back to being Mexico's most wanted man.