A new preschool opening this fall basing itself in the Arnold Arboretum is aiming to be the first licensed outdoor preschool in Boston. That's right -- the arboretum will be the students' classroom! "The best part about spending time in nature is that you never know what you'll find; at many schools all the lessons are pre-planned by the teacher, but in nature there's that sense of wonder when you see something unexpected or amazing," said Sarah Besse, co-founder of the Boston Outdoor Preschool Network (BOPN). "In nature, the teachers' role is not to 'deliver' pre-planned lessons, but rather to learn and explore with the children. Us teachers will follow the children's own interests, and help them how to go about finding answers to their own questions."