The 3,000-foot tunnel — which reached depths of around 50 feet underground at its deepest point — was equipped with lighting, electrical wiring, ventilation systems and a track system.

U.S. Border Patrol agents have uncovered a sophisticated underground tunnel stretching more than 1,000 feet into the United States from Mexico as part of a drug-smuggling operation in Southern California.

CBP says agents carefully mapped out the tunnel, which had a total length of 2,918 feet. Its dimensions were 42 inches tall, 28 inches wide and about 50 feet underground at its deepest point.