Did you know that a blue whale weighs about the same as 33 elephants? Get ready to find out even more fascinating facts about the ocean, its wildlife and the history of sea exploration.This visually stunning science guide takes you on an underwater voyage past coral reefs, submarine volcanoes and deep-sea fish. Learn about how tides and currents work, why the ocean is so salty, how humans have dived to the depths in submersible craft and much more!Each volume in the Factology series provides a fast-paced and fun introduction to its subject, explaining key concepts and highlighting significant events in a manner that is clear, accessible and entertaining.The KS2 and KS3 school curriculum is consulted when devising each volume, to ensure that the books cover important educational topics, making them a perfect teaching aid for learning history and STEM subjects.