The book by famous explorers of the world's oceans tells about the first discoveries of the Underwater Research Group - young enthusiastic friends - about the history of the creation and first voyages of the world famous scientific vessel "Calypso". Exciting documentary stories about travel for the treasures of sunken ships, descriptions of underwater flora and fauna , stunning facts about the impact of unusual elements on human physiology - all this reads like an adventure novel. The book contains extremely interesting material, while being extremely entertaining, replete with memories of funny and tragic incidents, of discoveries that revolutionized science, of the mysterious world of the deep sea.