The Organisation of African Unity, or OAU for short, is like a big club made up of all the countries in Africa. Just like how you have a club at school with some of your friends, all the countries in Africa decided to create one big club for themselves.
The club was founded in 1963 when 32 African countries came together to help each other out. They wanted to work together to solve problems like poverty, war, and disease. Imagine if you and your friends wanted to help people in your community who were struggling - you might create a club to work together and try to make things better, and that's what the OAU did for an entire continent!
One of the group's biggest goals was to promote peace and prevent wars between countries in Africa. They did this by creating something called a 'Charter' which was like a rule book for the club. Just like you have rules for your club at school, the OAU had rules that all the countries agreed to follow.
Another important thing the OAU did was promote economic development throughout the continent. This means they wanted to help all the countries in Africa become stronger and more prosperous. They did this by working together on projects like building roads, schools, and hospitals, and supporting each other's economies.
In 2002, the OAU was replaced by a new organization called the African Union, which continued to work towards the same goals. While the OAU may not exist anymore, it was an important symbol of unity and cooperation among African countries, which is a really good thing!