Imagine coming home from a long night at work. You haven't been sleeping well lately, so you practically collapse into bed. In an instant, the world transformed into a world of wonder and magic. Suddenly, the sky darkens and your worst fears, snakes, spiders, injured loved ones, start appearing right in front of you. You sit up in bed and scream. When you calm down, you realize it was just a nightmare. This phenomenon happens to many people every night. In fact, it is one of the most common sleep events. These visions, these dreams, appear to everyone every time they sleep, but few understand the science of their sleep and the meaning of their dreams. Webster's Dictionary defines sleep as “the natural periodic suspension of consciousness during which the strength of the body is restored. .” Brynie writes that the human body is controlled by a cycle known as the circadian clock. It corresponds to the 24-hour day and coordinates all the biological activities of life.(74-75). The sleep cycle is one of the most complex biological cycles that the organism carries out. It goes through five stages. Phases one through four last approximately seventy minutes (Brynie 14). In the first stage, the senses begin to shut down (Kallen 14) and the brain begins to "send slow amplitude signals." A person's eyes still move, and any interruption will startle the sleeping person. (Brynie 12). In the second phase of sleep “brain waves slow down and become theta waves”, which repeat 4-8 times per second. The sleeper at this stage still scares easily (Brynie 12). In the third stage, the sleeper begins to become more difficult to wake up. Delta rhythms occur. (Byrnie 13). In the fourth phase, the delta waves take over and the sleeper finds himself in the deepest part... in the center of the chart... characterized by very distinct waves. These waves also reflect actions within the dream. Climbing a ladder or stairway is reflected in strong vertical waves, and walking across plains is characterized by long wavelength waves with low amplitude (Kallen 24). Researchers believe that dreams serve a very specific purpose. They are necessary for the brain's "housecleaning" process. It is through dreams that researchers believe the brain selects, discards and stores memories. Experts say that it is not harmful to remember some dreams, but most dreams are often forgotten in the morning (Byrnie 16). In fact, those vivid images that are remembered have sparked incredible folklore about dreams. There are three overwhelming beliefs about dreams in popular culture. Most dreams seen in stories today are depicted as telepathic, prophetic, or inspirational.