Growing up we had more than one horse chestnut tree around our block on the northwest side of Chicago. As kids, we liked to collect the chestnuts when they fell in their prickly green covers. When we opened them, a richly colored, smooth and shiny brown horse chestnut was revealed. We collected the best examples of these. They also served as projectiles of course, to be thrown or batted at. We also had a treehouse in a horse chestnut tree in our backyard. The trees on our block were like friends, giving us their fruit, their leaves to collect and jump in, and their shade in the summer.