Diving can be dangerous when someone who is not trained engages in the activity. There are safety rules taught in class about which the general public is unaware. There are many organizations through which you can obtain training. These companies set the standards for the minimum level of education which must be provided during scuba diving classes. In this way the industry polices itself to assure that new divers are properly trained.
All instructors work through a certifying organization.
After you have received initial training, you can scuba dive in any country in the world. Any place that has access to either fresh or salt water is considered fair game. Most divers choose to travel to tropical destinations where the water is consistently warm and the climate inducive to outside activities. In these zones you can dive in magnificent colonies of coral which are beautiful beyond description. Diving can be relaxing and almost effortless in many of these areas.