U Thant
On January 23, 1971 U Thant categorically announced that he would "under no circumstances" be available for a third term as Secretary-General. For many weeks, the UN Security Council was deadlocked over the search for a successor before finally settling on Kurt Waldheim to succeed U Thant as Secretary-General on December 21, 1971 — Waldheim's 53rd birthday — and just ten days before U Thant's second term was to have ended.