The underwater world can be awe-inspiring, meditative, and a true escape from the hectic pace of the surface world. It can also be dangerous, especially when you lack the proper training or equipment to cope with changing conditions or emergency situations.

During recreational dives, you’ll carry a tank of compressed air toted on your back, a face mask that covers the eyes and nose, a snorkel to help you breathe, a pair of fins, a buoyancy compensator device (BCD), and weights. Other specialized gear may be used depending on the type of dive and the temperature of the water.

There are four “mini-histories” in the long story of man’s fascination with the sea, and each relates to one of the distinct forms of diving available today:

Recreational scuba diving consists of entering underwater with a steel or aluminum diving cylinder of compressed air, a dive computer, a buoyancy compensation device, and a full set of personal safety equipment. A scuba diver must be certified to use this equipment.

You can learn to scuba dive at a number of local schools and through renowned agencies like PADI, NAUI, and SSI. You must be at least 12 years old to enroll in a certification program, and you must pass a medical questionnaire that ensures you are fit to dive. You can also take 100-hour occupational courses that include conditioning, a swim test, and training in CPR and first aid. These courses are usually conducted in a swimming pool and are more structured than scuba certification programs.