Narco-tanks are home-made armored vehicles, also known in Spanish as "monstruo" for their hulking size. They reached peak popularity in 2011 as the Mexican military seized a garage from the Los Zetas drug-trafficking organization that was being used to construct the vehicles. At that point, criminal gangs could operate military-like vehicles out in the open with apparent impunity.
The Mexican military's subsequent crackdown on the creation of monstrous forced the practice even further underground. Narco-tanks are still produced, but today's versions have their armored paneling on the inside so as to not draw unwanted attention from rival cartels and the military.
Below is a breakdown of the various features that made narco-tanks into impregnable, drug-running beasts.