This is the flag of the United Nations Mission in Cyprus. It comes from a world where the United Nations took a more hard-line stance on the Turkish Invasion of Cyprus. United Nations task forces were sent in to protect Northern Cyprus against Turkish occupation. At the same time, additional troops were deployed to protect Cypriot independence from radical elements within Greece. Most critical of all, the UN Mission in Cyprus received military support from the United States. It helped that the United States pulled out of Vietnam earlier than it did in our world, and thus wasn't quite as war-weary.
Thanks to the United Nations' intervention Cyprus is a happily united and prosperous nation. Greece and Turkey were both put on probation following the intervention in Cyprus, but they were eventually readmitted to the UN. The United Nation would go on to institute reforms within itself following the events in Cyprus. The main aspect of the reforms was that only true democracies would be given a voice in the United Nations; the organization would also take a great stance to promote democracy through interventions such as the one in Cyprus. This stance resulted in fairer treatment for Israel and action against human right violations in the Middle East.
The flag contains the light blue and white colors of the United Nations flag. It also contains the outline of Cyprus and the nation's name in Greek.