[5] 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.

As with previous documentaries in the Walking with... franchise, Sea Monsters recreated extinct animals through a combination of computer-generated imagery and animatronics, incorporated into live action footage shot at various locations.

In addition to imagery from the series, the exhibition featured full-scale models of both modern and prehistoric sea creatures as well as behind-the-scenes information on how the animals were reconstructed and brought "back to life".

Whereas both of the previous specials took place on land and were confined to a single setting,[b] Sea Monsters focuses on the aquatic life of seven different geological periods between 4 and 450 million years ago.

Dubbed "Hell's Aquarium", this sea is determined to be the most dangerous due to the sheer number of different predators present, including 17-metre (56 ft) giant mosasaurs (Tylosaurus).

[9] Like the previous specials, Sea Monsters is a definite step away from traditionally narrated documentaries, such as the original 1999 series of Walking with Dinosaurs.

In comparison with the original series of Walking with Dinosaurs, Sea Monsters is considerably more action-oriented, with Marven frequently interacting with the animals.

Though entertainment and adventure is a bigger focus than in previous entries in the franchise, the series still ultimately aims to be an educational documentary, weaving facts into the action and intending to teach viewers about the extinct animals it portrays.

By the time Sea Monsters entered production, the team at Framestore were already familiar with what techniques to use due to their past experience on the previous series.

[1] As an example, the sea scorpions, an extinct group of chelicerate arthropods encountered by Marven in the Ordovician, were developed and refined based on the input from Simon Braddy, a palaeontologist at Bristol University.

Hoggart also believed the inclusion of a presenter in the previous series Walking with Cavemen (2003, featuring Robert Winston) to have been "silly" and wrote in regards to Sea Monsters that "if you are worried the horse might get tired, for heaven's sake don't dress it up in a costume.

[24][25] For his work in Sea Monsters and in the preceding Land of Giants, Nigel Marven was nominated for a Royal Television Society Programme award for best presenter (factual).

Defending Sea Monsters, Jasper James did not believe that the series was patronising, stating that "if you can enjoy the drama of a programme while learning something then that's great".

Sellers concluded that "this book would make a great addition to any high school teacher's library" and that "students could use it as a reference source, and they will definitely be captivated by the wonderful illustrations".

[3] Modern and prehistoric creatures were not presented just through photographs and renderings from Sea Monsters, but also in the form of full-scale models, created by Avalanche Studios, allowing visitors to see their size.

[35] In addition to depictions of the sea creatures themselves, the exhibition also included behind-the-scenes information on the technology and techniques used to bring the prehistoric animals "back to life".