Children's zoo in safari; a corner of imitation Africa in La Ronde; is pretty routine for adults but children get a thrill out of petting a real baby elephant. La Ronde; Expo's imaginative amusement area; is an expensive place to take children but there are exceptions: Children's World has a free playground with a marvellous slide - a gigantic; brilliantly colored snake which youngsters hurtle through from tail to mouth. Crowds are spread evenly through area.