What does it sound like at the bottom of the ocean? How does it feel to swim with a humpback whale and her calf? What does an octopus' tentacle feel like when it wraps itself around you? Come and find out in this 12-part series. Wildlife filmmaker, zoologist and broadcaster Hannah Stitfall wants to take you to the world beneath the waves. Over 12 episodes, she'll be meeting freedivers, submarine pilots, whale experts, ship captains, marine biologists, and more, hearing the most mind-boggling stories about the oceans and the astonishing creatures that call them home. The hypnotic sound design and immersive storytelling will take you right there - from the Lost City to Galapagos, from the Mariana Trench to the Antarctic. Brought to you by Crowd Network and Greenpeace UK, which helps us tell these stories beautifully and responsibly. Producer: Anna Staufenberg. Executive producer: Steve Jones. Mixing and sound design: Anna Staufenberg. Archive courtesy of Greenpeace.