How many tentacles do octopuses have? Did you know that humpback whales are famous for their singing? What is the purpose of the seahorse's small dorsal fin? These and many other questions will be answered in this book, devoted to the underwater world, to be discovered through 10 fabulous pop-ups. Many inhabitants of the oceans, from tropical fish to sea turtles, and other curiosities told through many colourful illustrations, enriched by spectacular pop-ups. Plus, to delve deeper into the various subjects, there are plenty of curious and interesting anecdotes, making this volume a stimulating read and an opportunity to play.