Look Inside the Underwater Drug Smuggling Tunnel Between Mexico and the US

— -- Here's a first look at the intricate underwater tunnel that drug smugglers built into a canal at the US border -- the first time that a tunnel was built into the All-American canal.

Investigators discovered a trove of equipment used to navigate the route near Calexico, about 122 miles east of San Diego, including scuba diving gear, a re-breather mask and 25 packages of cocaine held down by weights, officials said.

“This is the first time where a tunnel was built into the All-American Canal,” Assistant U.S. Attorney Sherri Hobson told ABC News. “This is just evidence to show that drug traffickers will do anything, go over the border, through the border and even go under the water. This was a very creative way to smuggle drugs.”

The tunnel was almost 150 feet long, stretching from Mexicali, Mexico, under the border and ending at the south bank of the canal. The drugs were put and transported on a trolley system located inside of the tunnel.

Evelio Padilla-Zepada, a 28-year-old Honduran national, was found in a soaked wetsuit along the All-American Canal in Calexico.

Padilla-Zepada pleaded guilty Wednesday in federal court to one count of possession of drugs with intent to distribute for smuggling 55 pounds of cocaine through the underwater tunnel.

Border Patrol agents arrested him on April 25 while patrolling east of the Calexico West Port of Entry.

Officials estimate the value of the drugs, packaged in gift wrap and submerged using weights, to be at nearly $1.8 million.

Padilla-Zepada faces a maximum of 20 years in prison and up to $1 million fine.

He will be sentenced on Dec. 7 and will be deported back to his county of citizenship after serving his time in jail, added Hobson.