source: http://www.bet.com/News/Photos/NewsFlipbookNBAAllStarDunks
One of the many innovations that began in the ABA and continued after the merger with the NBA was the Slam Dunk contest. It was first held at McNichols Arena in Denver during half time of the ABA All-Star game. The contest only lasted one year then was resurrected by the NBA in 1984. The winner of the first Slam Dunk contest was Julius Erving due in part to his dunk leaping from the free throw line which can be seen at the 5:30 mark of the video.