View from the Tijuana side, Mexico, on October 12, 2017 of prototypes of US President Donald Trump's US-Mexico border wall being built near San Diego, in the US. Following up on President Donald Trump's campaign promise to build a wall along the entire 3,200 kilometre (2,000 mile) Mexican frontier, the Department of Homeland Security began building prototypes for the barrier along the border in San Diego and Imperial counties, as it announced in August. / AFP PHOTO / GUILLERMO ARIAS (Photo credit should read GUILLERMO ARIAS/AFP/Getty Images)