Marseilles

I’m going with two friends to Europe at the end of the summer/early fall. As of now the cities are as follows: Rome, Venice, Munich, Zurich, Milan, Marseille, Paris, London, Dublin.

Paris, Rome, Venice are all pretty much decided what we’re doing, but I was wondering if anyone knew of fun things to do/see in the rest of the cities (especially Milan, Marseilles, and Munich).