06/08/1948
https://www.presidency.ucsb.edu...
"Now, Therefore, I, Harry S. Truman,President of the United States of America, under and by virtue of the authority vested in me by section 2 of the act of June 8, 1906, 34 Stat. 225 (16 U.S.C. 431), d..."
"Warning is hereby expressly given to all unauthorized persons not to appropriate, injure, destroy, deface, or remove any feature of this monument and not to locate or settle upon any of the lands rese..."
"I designate the week beginning April 11, 1948, as Pan American Week"
"Now, Therefore, I, Harry S. Truman, President of the United States of America, do hereby proclaim Wednesday, April 14, 1948, as Pan American Day"