Donald Trump on Monday became the first sitting U.S. president to visit the Western Wall – the holiest site where Jews can pray – and left a prayer note there in accordance with Jewish custom. Located in Israeli-annexed east Jerusalem, the Western Wall is a section of one of four original retaining walls King Herod built in the first century B.C. to support the Temple Mount. It is also the only remaining portion of the Second Jewish Temple, which stood in Jerusalem until the Romans destroyed it in 70 A.D. as they put down a Jewish revolt. It has been...