What are your favourite free, outdoor playgrounds in Singapore?

My boy loves waterplay and we do not own a car. Below are his favourite spots via Train: Splash N Surf is a wet playground at Kallang Wave (Stadium station). It has a 0.5m kids pool and 4 slides of various heights suitable for 3-12. He seem to enjoy it very much even when he was 20 months old. Water fountain at Bugis Junction (Bugis station). There are always kids getting drenched in the mist of dodging the water spouts. Typically we pack extra clothes in his diaper bag so having fun can be quite random. Did you mention outdoor? lol... He loves going airport to watch aeroplanes and there is a indoor children playground to Terminal 1. There are many malls that has outdoor playground such as City Square Mall, IMM, Seletar Mall, Nex, etc. Personally, I feel my 3 yo boy enjoys all playgrounds including neighbourhood hdb playgrounds. It doesn't need to be fancy to have fun. My 2 cents.