How sonar changed the world

Sonar is a system that uses transmitted and reflected underwater sound waves to find submerged objects. First sonar device was created 1906 but many nations didn't take a interest till World War One,because of the use of submarines durning World War One which during the time before sonar it was extremely hard to see subs till they were right on top of you.

The first Sonar for locating submarines was made by Paul Langevin in 1915 called echo location. Sonar was also used to map out the ocean floor,find sunken ships.Sonar changed warfare and underwater exploration as we know it with out it ships would still be at a disadvantage when trying to locate subs and we wouldn't know what was on the ocean floor without it.