UNITED STATES—The United States Customs and Border Patrol (CBP) discovered the longest recorded man-made smuggling tunnel on the southwest border of the U.S. and Mexico on Wednesday, January 29.

According to Customs and Border Protection, the tunnel was found in August 2019 by Mexican authorities and is 5.5 feet high, 2 feet wide and is 70 feet below the earth’s surface. It has an extensive rail and cart system, high-voltage electrical cables and panels, forced ventilation, an extensive drainage system, and an elevator at the tunnel entrance.

The San Diego Tunnel Task force began mapping the tunnel after it was discovered. The tunnel extends a total of 1,313 meters or 4,309 feet long. The next longest tunnel in the U.S. was discovered in 2014 and is 2,966 feet long.

8NewsNow video shows length of the tunnel spanning from Tijuana, Mexico to San Diego, California; it runs over three quarters of a mile long. The exit of the tunnel was located in an old Otay Mesa warehouse district on the U.S. side of the border and was covered with some sandbags.

VIDEO: U.S. Customs and Border Protection announced the discovery of the longest smuggling tunnel ever discovered along the Southwest border.

Posted by 8 News Now on Thursday, January 30, 2020

According to Cbc.ca, it is required by federal law that once a tunnel is discovered, U.S. authorities must fill the U.S. side of the tunnel with concrete.