6. Disney World Tunnels
After Disneyland became such a success, Walt noticed one issue which gave him headaches; characters running through the wrong lands to get to their destination. He did not want to break the magic of having costumed characters, such as Belle, run through a world designed for Ariel, so he created an elaborate tunnel system in the Florida based park to ensure that characters only appeared where they were meant to. This helps keep the illusion of the characters from shattering. In addition, it meant the entire park had to be built on a gentle incline to accommodate the tunnels.