Scuba diving offers a wonderful way to view the intriguing underworld of any ocean or lake. To be a competent scuba diver, one should take a scuba certification class offered at a wide array of diving schools worldwide. Scuba certification classes can help newcomers to the sport prepare for the dangers they may encounter. Advanced certification classes are also available to help experienced divers to continue to gain more scuba diving knowledge and experience. Scuba dives should never dive alone and they should always make certain their gauges, tanks, and other equipment are functioning properly. The average person may think that sharks and other large fish might present a clear and present danger for scuba divers. To the contrary, sharks and other large fish account for almost none of the 100 scuba deaths that occur each year, according to the Diver`s Alert Network. Most shark attacks occur when the victims are standing or swimming in water close to the shore. The greater concern for the perils associated with scuba come into play if someone has not been properly trained or certified. Such a person may ascend too quickly to the water`s surface, resulting in the dreaded condition known as the bends, a decompression sickness with effects that can range from discomfort and vomiting to paralysis and even death. Most diving injuries pertain to ear problems and sinus problems. When a person experiences middle ear pain and discomfort due to the pressure changes inherent in scuba diving, doctors refer to this as a "squeeze." Other typical injuries affiliated with scuba diving are cuts and scrapes from fish, coral, and shipwrecks.