Driving across the North American Heartland, surrounded by prairie, it is almost impossible to imagine that once this was once a huge inland sea. The Western Interior Seaway, which split the entire continent of North America in half, once teemed with predatory creatures - fanged fish and turtles the size of small cars; prowling sharks and giant squid; hungry plesiosaurs and immense crocodiles. At the top of this prehistoric food chain, stretching up to nearly 15 metres (50 feet) and weighing a hefty 50,000 kilograms (50 tonnes), ruled the mighty mosasaur, the T-Rex of the sea.

Through a cooperative partnership with the Canadian Fossil Discovery Centre (CFDC), home to 'Bruce', the world's largest mosasaur skeleton, author Larry Verstraete and illustrator Julius Csotonyi combine fascinating facts, astonishing discoveries, and the latest paleontological information to bring the ancient marine creatures of the Seaway to vivid life.