San Ysidro, California (CNN)President Trump called for a "big, beautiful wall" between the United States and Mexico. And the vision is now morphing into reality with the construction of eight 30-foot tall prototypes in no-man's land on the border south of San Diego.
5 opinions from in the shadows of Trump's border wall prototypes
The concrete poured for the sections of wall is now hardening ahead of official tests to see if the prototypes can be scaled, dug under or simply blown up. As that happens, their arrival on the landscape is also hardening opinions.
Here are views from five people we spoke to in the shadows of the wall.
"The wall is a message for Mexicans and people from Central America to stay away from the US. I don't think the wall will be effective because drugs get in through other ways and migrants will always find a way into the US right under the noses of authorities."
Adriana Alvarez was born in Mexico and moved to San Diego six years ago.
"These walls are an insult to Mexico. It's an insult to a country that has good relations with the US both generally and on the border. They do nothing to build on that relationship."
Victor Clark-Alfaro, professor of Latin American studies at San Diego State University, is a Tijuana native who crosses the border daily to teach.
"The experience that we've had with border walls over 20 years, 25 years now, is that border walls don't work. People who are desperate and in need find a way to make it into the US to get work and provide for their families. What it will do is worsen conditions for migrants crossing the border."
Pedro Rios is a director of the US-Mexico border program of the American Friends Service Committee advocacy group.
"Field agents will tell you that the wall is necessary, it's another tool to protect the entire border."
Carlos Diaz is a spokesperson for Customs and Border Protection.
"I don't think the wall will change anything with regard to migration. It upsets me that they're building it because it won't help either country."
Adriana Altamirano, 15, from Rosarito, Mexico, comes to shop in San Ysidro.