Since 2015 tunnels have run under the border from Mexico to America. Donald Trump has made building a border wall one of his key priorities to tackle illegal immigration and drug trafficking. On 30 January, US officials said that they had discovered the longest smuggling tunnel ever. Stretching for 1,313m, it had a lift, rail track, drainage, air ventilation systems and high voltage electrical cables. The passageway connected an industrial site in Tijuana to the San Diego area in California. Mexico's Sinaloa cartel, one of the largest drug-trafficking organisations in the world, operates in the area. Its founder and long-time leader, Joaquin ‘El Chapo’ Guzman, is serving life in prison in Alcatraz. Mexico's murder rate rises annually - 2019 was the bloodiest year on record, with 34,582 killings. Much of the violence is linked to criminal gangs who engage in drug trafficking, kidnappings and extortion of local businesses and farmers. See