The child actors were wonderful in this movie! I discovered the themes of this movie are the importance of always keeping the wonderment, joy and imagination of childhood in your heart. The movie conveys it in such an exciting yet touching way. And, the second theme becomes apparent towards the end, SPOILER AHEAD: as the children allow themselves to grow up. They learn that growing up is just as valuable -- it's a different type of journey to be treasured, as long as you keep youthfulness alive inside you.