Scuba diving is a sport/pastime that allows people to dive and swim under water for specific periods of time. Scuba (Self Contained Underwater Breathing Apparatus) equipment feeds the diver oxygen so that they can effectively breathe underwater without having to come up for air.
You can scuba dive just about anywhere - in seas and in fresh water locations. It is, however, vital not to try out scuba diving without proper training and instruction from a qualified individual and/or company. This can be a dangerous pastime if you do not know what you are doing, how to handle your equipment and what to look out for when you are underwater. Some people will learn how to scuba dive whilst on holiday and others will learn at their local swimming pool before they go away.
Many people simply scuba dive for fun - this really is the only way to enjoy underwater worlds. Obviously it is important to match the depth that you dive here to the level of experience and training you have. Scuba diving can also be a career and there are opportunities for commercial divers in all kinds of industries including the military, oil companies, bridge building companies, emergency services and marine biology.