Tell about underwater explorations?

Tell about underwater explorations?
Man has always tried to explore what is above and below the firm earth, the sky and the deep seas. Exploring the oceans has never been an easy task. Till the present century, the only way to do that was by lowering instruments on lines from ships. Sonars, which used sound waves to detect details on the sea bed became popular after the First World War. Other instruments which are used for exploration include thermometer, current meter and cameras. Nowadays, oceanography is mostly done from satellites and it can measure the height of waves, temperatures etc, and can even detect the presence of shoals of fish!

In spite of the use of instruments, people want to go down to the depths of the sea to explore it for themselves. Diving suits were developed for the purpose and air for the diver was supplied from the ship by means of a hose. The SCUBA gear, made later, improved upon this and carried its own air supply. Divers have to be specially trained and prepared to adapt themselves to the great pressure of water on their bodies. Along with these developments, inventors also made containers to carry men breathing air at normal pressure under the sea.