Find out how a submarine works in this interactive book with flaps and holes. Lift flaps and peep through holes to explore with a little sub on a deep-sea dive. Find out how the sub works by opening it up and peeping inside at the cockpit and the ballast tanks, and help the crew collect deep-sea samples using the mechanical arms. There's lots to learn about marine life, too - investigate what an octopus is guarding, meet a hammerhead shark and switch off the sub lights to see all the glowing creatures in the dark.