The ocean is filled with giant, strange, and scary creatures such as whales, octopuses, and sharks—but the prehistoric megalodon was powerful enough to crush a killer whale. Other sea beasts of the past could hold their own against even the most mysterious of modern sea creatures. Sea scorpions had claws the size of tennis rackets. Tanystropheus used its long neck to catch fish from land. And Leedsichthys had as many as 40,000 teeth! What would happen if these extinct beasts came to life? Imagine prehistoric sea beasts chasing dolphins, fighting crocodiles, and hunting humpback whales—and learn all about the prehistoric creatures of the deep!

A companion volume to the 3-D "Sea Monsters" film reveals the terrifying predators that lurked in the underwater Cretaceous world, in a volume that also profiles the scientists who study these ancient monsters and the technology that made the film possible.

Color artwork and detailed captions journey underwater to capture the prehistoric world of an array of extinct animals, in the companion volume to the Discovery Channel special

In prehistoric times there existed creatures bigger and often fiercer than dinosaurs, whose exploits have inspired more terrifying legends than any other group of animals. Their watery home has kept them hidden from view - until now. Monsters once again recreates the prehistoric world, giving us an insight into the underwater environment of that time and the strange and fascinating creatures that dwelt there. The leading wildlife television presenter, Nigel Marven, explores their world through a series of encounters, where he dives deep into the past and swims with these extraordinary reptiles and mammals. From the fearsome hunter, Liopleurodon, one of the biggest predators that ever existed, to Megalograptus, the most vicious of the spiny sea scorpions, the deadly prehistoric seas are vividly brought to life as we see these creatures through Nigel's eyes. Some of the ancestors of these predators exist today, but even the great white shark and blue whale cannot come close in threat and size to these prehistoric species. reconstruction of these creatures, with details of the modern sites, from New York to Egypt, where water once covered the land.

Find out how sea creatures from our planet's past lived, fought, and died.

A young female sea dolly is born in the shallow waters of a prehistoric Kansas Mesozoic-era lake and learns to survive after encountering a variety of predators and other underwater dinosaurs from that ancient time period.

Swim in the murky underwater world with prehistoric creatures who fought for their survival in Age of Ancient Sea Monsters from PNSO Field Guide to the Ancient World. See the evolution of these terrifying sea creatures who lurked beneath the ripples and waves half a billion years ago.