The world of scuba—Self-Contained Underwater Breathing Apparatus—offers adventures that are as diverse as the planet’s many ecosystems. It’s a sport, a hobby, a way of life and an opportunity to explore some of the ocean’s most beautiful and fascinating creatures in places where no one else can.

Divers need a steel or aluminum diving tank filled with compressed air and scuba equipment such as a mask, snorkel, fins, dive computer, buoyancy compensator device, regulator, weights and depending on the temperature an exposure suit. Recreational divers may purchase their own scuba gear or rent it from a scuba shop. Getting certified is the wisest thing a beginner can do before he or she goes exploring underwater. It will maximize the pleasure and minimize the risk of injury or even death. According to the Divers Alert Network, a scuba-focused think tank, there are probably fewer than two deaths for every million recreational dives worldwide. Generally speaking, most diving mishaps are caused by bad judgment calls rather than accidents resulting from lack of training.

The earliest diving was breath-hold (free or skin diving), and it remained the main method of exploration until the 16th century when people began to use leather helmets that allowed them to stay underwater for short periods—limited by their ability to breathe under pressure. In the 19th century, the Seibe Improved Diving Suit—a wetsuit with a hood and an air cylinder—was introduced, along with the first diving school. In 1908, physiologist John Scott Haldane publishes his landmark paper “The Prevention of Compressed Air Illness” laying the groundwork for staged decompression tables that will save countless lives over the next century.