This resource explains why Earth has 24 time zones, introduces GMT, the Prime Meridian, longitude and the International Date Line, and tours world cities at the same moment in time. It is a ready-to-teach PowerPoint scaffold for an hour-long geography lesson on time zones. Children solve time-zone calculation problems as detectives and then plan a round-the-world video call that works for friends in New York, Paris and Tokyo. A fascinating-facts section adds wow moments to share at home.