S1, E2: The world today is obsessed by time. Johnson boards a submarine to discover what a lack of natural light means for a sailor's working day and visits Heathrow, the world's busiest airport, to try to get timings right at air traffic control. The story of getting a grip on time is full of curious garage tinkerers. One of them, railway clerk William F. Allen, was so exasperated by the chaos caused by the 8,000 local times zones in the U.S. that he fought tirelessly to standardize time into four zones. Learn how advancements in navigation, the way we work, technology and travel would have been impossible without the unsung heroes of time.