Eight prototypes of US President Donald Trump's proposed border wall were unveiled on Thursday. The concrete and steel structures, erected in a remote area in San Diego, will be tested for 30 to 60 days to determine which design meets the needs to secure the border, US Customs and Border Patrol Protection said in a statement. The models were erected in the wake of Trump's January 25 executive order instructing the Department of Homeland Security to build a wall along the nearly 2,000-mile border with Mexico.