The tower of Babel was the first recorded multicultural project.
Babylon was once an ancient homogenous white society. It had a high civilisation that had existed for centuries, with the other races being kept outside of it. Eventually though, the Babylonians got lazy and instead of keeping the tribes outside, they started bringing them in, to work.
Soon, it became easier to let the other peoples start dwelling within the city, and they went from being kept outside to becoming a part of the civilisation. Finally, people started to forget who they were and started thinking they were all one. They decided to take what was separated by God and Nature and unite it by man.
They embraced diversity.
But instead of improving their nation, it utterly destroyed them and those that came after them.