Event:
U.S. Post Office issues 1st books of postage stamps
More Notable Events on April 16:
1980 Arthur Ashe retires from professional tennis
1972 2 giants pandas arrive in U.S., from China
1962 Walter Cronkite begins anchoring CBS Evening News
1908 Natural Bridges National Monument forms near Lake Powell, Utah
1900 U.S. Post Office issues 1st books of postage stamps
