In Singapore, there is full-day school for 18 month olds. I didn't do it, but have friends who put them in 12-hours a day, 5 days a week. They learn to eat, nap, bath and potty-train. At that age, there's just a lot of play, so I don't think of it as school, but it's nice to know that there are caring, professional adults that will take care of your children in a clean, stimulating environment. Having only just potty-trained my 4 year old, I certainly wish we had such options in Hong Kong!