He continued his winning streak in the 1971–74 competitions. In 1975, Schwarzenegger was once again in top form, and won the title for the sixth consecutive time, beating <answer>Franco Columbu</answer>. After the 1975 Mr. Olympia contest, Schwarzenegger announced his retirement from professional bodybuilding.
Who did Schwarzenegger beat to win his sixth Mr. Olympia in a row?
Franco Columbu