With the increasingly strong development of science and technology, up to now, a lot of inventions have been made, helping a lot for human life. Among them are inventions related to the ocean and one of them is a submarine. Submarine . The world's first submarine was invented in 1776, with an egg-shaped 2m high and 0.9m wide. According to the development of society, today submarines have been improved into modern equipment. Thanks to the submarine, the old days the American fighting was victorious. To this day, submarines have helped people explore the deepest places of the sea, help people exploit, learn deeply about marine creatures. It can be said that the submarine is one of the greatest inventions that man has made.
