In this photograph by Jack Kightlinger, First Lady Pat Nixon celebrates her birthday on board Air Force One on March 16, 1974 en route to South America. Also on board were staff members, including Col. Jack Brennan. Born Thelma Catherine Ryan, Mrs. Nixon was nicknamed "St. Patrick's Day Babe" by her father due to being born the day before St. Patrick's Day. The shortened version, Pat, stuck with Mrs. Nixon the rest of her life.