On April 19, 1933, the United States effectively went off which monetary system?

Which actor starred in "Ambush at Cimarron Pass," "Kelly's Heroes" and "City Heat"? Amelia Earhart appeared on a 1963 issue of which type of special-purpose U.S. stamp? Amelia Sedley, George Osborne and Becky Sharp are characters in which novel? How many amendments make up the U.S. Bill of Rights? American architect Daniel Burnham was director of works for the 1893 World's Fair in which city? American astronomer Asaph Hall discovered which planet's two moons in 1877? "American Caesar" is a biography of which general, who told Congress "Old soldiers never die"? What was the middle name of American catalog merchant Aaron ___ Ward?