 On December 22, British Prime Minister Winston Churchill secretly arrived in the United States aboard and flew the remaining to Washington, where he stayed with President Roosevelt in the White House for the Arcadia Conference.At 4 p.m. on December 24, the southeast and southwest gates of the South Lawn were opened, and between 20,000 and 40,000 people entered the grounds (searched and watched over by U.S. Army soldiers, D.C. Metropolitan Police, and agents of the Federal Bureau of Investigation).Another 2,000 to 3,000 people waited outside the fence.