The so-called “border wall” was a signature of Donald Trump’s presidency. On Tuesday, with just days left in office, he will head to South Texas to visit the wall and point to what has been constructed — the concrete and steel, which are symbolic of his crackdown on the US immigration system. The World’s immigration editor Monica Campbell offers a reality check on the wall and how some federal judges have recently rejected the administration’s final attempts to toughen US immigration rules.