SAN DIEGO (CBS 8) - Otay Mountain will be ground zero for the first prototype border walls as President Donald Trump scrambles to find financing to start construction.

CBS News 8 was given exclusive access to the spot where some 20 prototypes are planned to be built by the end of June.

The location is about two miles east of the Otay Mesa international border crossing and is literally a stone’s throw from some Tijuana neighborhoods.

Border Agent James Nielsen escorted our crew along the rugged terrain at the foot of the mountain. Here, the border fence runs for several miles and then simply ends.

“Really, the only law enforcement out in these mountain areas out here is the U.S. Border Patrol,” said Nielsen.

Fourteen miles of primary fencing could be replaced with a new border wall if funding is identified. Another 14 miles along the San Diego border would be reinforced.

“If you put a fence through here, well now we have a road that goes through here also and that road give us a baseline of enforcement,” said Nielsen.

The spot where the prototype walls are planned is close to Tijuana neighborhoods where agents have been attacked in the past by rock throwers.

The prototypes have to be built within 200 feet of the existing border fence because there’s only a narrow strip of federally owned land to build on. The property farther to the north is owned by either SDG&E or private developers.

“We have to patrol the area regardless if there’s a fence or no fence. We have to still work the area because you don't know what these criminal organizations are going to do,” said Nielsen.

Some of the prototypes submitted include traditional wire fencing, others are made of common cement blocks. One rendering looks more like the wall of China.

But most have one thing in common: they're designed to keep people out.

Professor Eric Frost teaches graduate studies in homeland security at SDSU. He said most of the prototypes he's seen are what he calls “dumb walls.”

“Most of the designs it will make almost zero difference,” Frost said.

“You can go over a wall, you can go under a wall and you can go through the normal border crossing very simply,” Frost said.

The professor would rather see money spent on a smart wall, one that would actually make money in a collaboration with Mexico.

“The wall on the south side would be a great place for solar panels, not on the north side but on the south side. So, the wall is generating money,” said Frost.

A wall with a monorail on top could move people east and west, for example. A wall fitted with seismic sensors could predict earthquakes.

One prototype looks more like a gateway than a wall. It has a transportation loop connecting Mexico and the USA.

“Our relationship with Mexico is incredibly power and positive,” said Frost. “We both have challenges and how do we solve them together?”

The current prototype plan released by the Department of Homeland Security is labeled "pre-decisional" and it is subject to change.