On This Day: 20 April 1971 ---------- records "We've Only Just Begun" ?

Questions

Coca-Cola is created (it had cocaine at the time)?

First Lt. William L. Calley, Jr. found guilty in the MyLai massacre?

Last US troops leave Vietnam, 9 yrs after the Tonkin Resolution?

Mariner 10, Mercury flyby?

Sir John Hawkins, wrote first history of music in English, born?