A BBC documentary trilogy about wildlife presenter Nigel Marven's travels to seas of the past. Computer-generated imagery is used to create the spectacular creatures he encounters. A BBC documentary trilogy about wildlife presenter Nigel Marven's travels to seas of the past. Computer-generated imagery is used to create the spectacular creatures he encounters. A BBC documentary trilogy about wildlife presenter Nigel Marven's travels to seas of the past. Computer-generated imagery is used to create the spectacular creatures he encounters. A BBC documentary trilogy about wildlife presenter Nigel Marven's travels to seas of the past. Computer-generated imagery is used to create the spectacular creatures he encounters.