London's Heathrow Airport is the world's busiest and home to one of the tallest terminals - T5. NGC reveals how ingenious breakthroughs enabled engineers to build the super structure. With its enormous free span roof, automated baggage system and robotic vehicles, T5 can feed 30 million passengers through Heathrow. Using CGI animation and on-location filming, you'll see the stunning innovations that changed airports forever and enabled them to grow - from big to bigger to biggest.