About the book: 1961 / This book was written for those who want to know everything: why the plane flies, why they dig canals, how the underwater world was discovered. And it was discovered how they discover everything unknown - long, difficult, dangerous. Different people sank to the bottom of the sea, and they had different goals. Some were attracted by sunken treasures, others were attracted by the opportunity to fight invisible, striking from under the water, others simply sought to see and learn what no one had seen or known before them. Centuries passed. The diving bell and the first hidden ships were replaced by nuclear submarines, scuba gear and bathyscaphes. A man from a rare guest turned into a master of the depths. He raises sunken ships from the bottom, searches for oil there, excavates ancient cities, protects the borders of his homeland under water... These stories are about how man penetrated into the depths of the seas, how he learned to swim, work and live under water.