Decolonisation of Oceania
The decolonisation of Oceania occurred after World War II when nations in Oceania achieved independence by transitioning from European colonial rule to full independence. While most of the countries of Oceania have a specific independence day, the independence of Australia and the independence of New Zealand were a gradual process and cannot be associated clearly with a specific date.
Source: Wikipedia — Decolonisation of Oceania (CC BY-SA 4.0)