Today ballparks feature padded walls and a warning track to preserve the health of MLB players. In the 1920's . . not so much.
While playing against the Washington Senators in Griffith Stadium on July 5th, 1924, Yankees right fielder Babe Ruth went after a slicing foul ball off the bat of Joe Judge. Ruth didn't get the ball, but he did find the outfield's concrete wall. He was knocked unconscious and lay prone on the field for as much as five minutes (!) before being revived.
An interesting bit of trivia about that day: future Negro League legend and MLB Hall of Famer Buck Leonard was in the right field stands that day, cheering on Ruth. During his lifetime Ruth had a large African-American following, in part because of the (mistaken) rumour that he was part African himself.