Sea Monsters (full title Sea Monsters: A Walking with Dinosaurs Trilogy), marketed as Chased by Sea Monsters in the United States, is a 2003 three-part nature documentary television miniseries created by Impossible Pictures and produced by the BBC Natural History Unit, the Discovery Channel and ProSieben. Following in the footsteps of The Giant Claw (2002) and Land of Giants (2003), special episodes of the nature documentary series Walking with Dinosaurs, Sea Monsters stars British wildlife presenter Nigel Marven as a "time-travelling zoologist" who travels to seven different periods of time in prehistory, diving in the "seven deadliest seas of all time" and encountering and interacting with the prehistoric creatures who inhabit them. The series is narrated by Karen Hayley.