My new game - what tree is that?

After too many years in Dubai where I seem to have spent most of my tree watching time looking at date palms, and the occasional oleander, I find myself unfamiliar with many trees - especially European ones. This, I am told, is a horse chestnut, spotted today when I was walking in the park in a brief gap between classes. It was warm and sunny then. During my last class the thunder was so loud I think it entered the room and then, when I got home, the paths were covered in hail stones. You've got to love spring :)