Misc: who was first four-time winner of the indianapolis 500?

Questions

14 March 1971 South Vietnamese troops flee ---------- ?

14 March 1971 The Rolling Stones leave England for ---------- to escape taxes ?

15 March 1971 ---------- make their debut on the Internet ?

22 March 1971 ---------- performs nuclear test at Eastern Kazakhstan/Semipalitinsk USSR ?

23 March 1971 USSR performs ---------- nuclear test ?