Tijuana and San Diego share a border, making it relatively easy for drug smugglers to dig a tunnel between the two cities.

On Tuesday, U.S. authorities shut down a 600-yard underground passageway connecting Tijuana to San Diego, after seizing 10 tons of marijuana as it was being loaded out of the tunnel's California side. Overall, U.S. and Mexican officials were able to capture 30 tons of the narcotic in the raid.

"It's not a good day for the cartels," said Immigration and Customs Enforcement Director John Morton. "They now can't move that size of drugs without digging a tunnel for 600 yards. It backfired on them."

Over the past four years, 75 tunnels have been discovered between Mexico and the United States. Read on to see a video of the latest, which featured lighting, ventilation and a crude rail system.