US President Donald Trump signed his name on a newly constructed section of the US-Mexico border wall yesterday, declaring it would be virtually impenetrable.
The 30ft-high barrier wall, made of concrete-filled steel bollards, replaced a previous barrier that illegal immigrants had been able to breach with the use of blow torches and saws.
"It was like a sheet metal, and people would just knock it over, just routinely. When the wall is built, it will be virtually impossible to come over illegally. It's the Rolls-Royce version. It's filled with a very powerful concrete," Mr Trump said.
He said the new wall in Otay Mesa, a community in San Diego, had concrete deep under ground to prevent tunnels.
"It's designed to absorb heat, so it's extremely hot. You won't be able to touch it. You can fry an egg on that wall. This wall can't be climbed," he added.
Mr Trump said he had wanted to paint the wall black, but it was too costly, so it was "a good, strong rust colour". He had also wanted a solid concrete block but border agents had asked for slats so they could see problems on the other side.
"We actually built prototypes and we have, I guess you could say, world-class climbers. We had 20 mountain climbers, that's all they do, they love to climb," Mr Trump said.
"Some of them were champions, and we gave them different prototypes of walls, and this was the one that was hardest to climb. One thing we haven't mentioned is technology. They're wired so that we will know if somebody's trying to break through."
Lt Gen Todd Semonite, chief of engineers of the US army, suggested the details should remain secret. "Sir, there could be some merit in not discussing that," he said.
Mr Trump hopes to build up to 550 miles (885km) of wall along the 1,954-mile (3,1544km) border by the end of next year.
His administration has so far built 66 miles (106km) of wall, has 251 miles (404km) under construction at 17 sites, and has contracts for 163 miles (257km) planned in the next 90 days. Crews are installing 270 panels a day, each one with eight bollards.
(© Daily Telegraph, London)