SAN DIEGO -- One of the busiest and most dangerous stretches of border fence is being beefed up, 10News reported.

The area, known as Smuggler's Gulch, is located just south of the Tijuana River Valley Park and is a geographically desirable spot for smugglers, according to authorities.

Former congressman Duncan L. Hunter said, "This canyon, Smuggler's Gulch, was a place that echoed with cries of people who were being robbed, raped and murdered by the border gangs. Some of the gangs carried automatic weapons."

It's a large area of land that sits along the border between San Ysidro and Imperial Beach -- 14 miles that have been problematic for U.S. authorities.

Brig. Gen. Kevin Ellsworth of the National Guard said, "The National Guard has been involved in border infrastructure for 15 years. To see this project come to fruition is pretty amazing."

The once open, hilly and dirt terrain has been replaced with paved roads, stadium lighting and a 20-foot metal fence.

10News learned that about 500 feet of the 14-mile stretch is being met with some challenges.

"This area had a historic set of bunkers called Bunker Hill. They were cement bunkers that were put in during World War II to protect against what we thought might be an attack after Pearl Harbor. Because they have historic significance, we haven't sewn up that last small piece of border," said Hunter.

The project entailed moving 1.3 million cubic yards of dirt, all while protecting the environment and San Diego County.

U.S. Rep. Duncan D. Hunter said, "San Diego families will sleep safer and better because of this border fence. It's pretty simple: fences make a safe San Diego."