A large cross-border tunnel connecting Tijuana in San Diego was found

San Diego (AP) — US officials announced on Monday the discovery of an underground smuggling tunnel on the Mexican border. It runs the length of a soccer field in US soil to a warehouse in an industrial area.

The cross-border tunnel from Tijuana to the San Diego area was built in one of the most fortified areas of the border, demonstrating the limits of the border wall of former President Donald Trump. It is believed to be effective against small, coarsely constructed tunnels called “Gopher Halls”, but the walls are not comparable to the more sophisticated walkways that run deep underground.

Authorities have discovered about 15 sophisticated tunnels on the California-Mexico border since 2006, featuring lighting, ventilation, railroad tracks, hydraulic lifts and more.

Many tunnels, including those announced on Monday, are located in San Diego’s Otaimesa Industrial Zone, where clay-like soil helps excavate and warehouses provide cover.

Cross-border corridors date back to the early 1990s and have been used primarily to smuggle tons of marijuana. The US Drug Enforcement Department said in 2020 that they were commonly found in California and Arizona and are associated with the Sinaloa Cartel in Mexico.

Federal law requires US authorities to fill the US side of the tunnel with concrete after the tunnel is discovered.