Waterfalls have profound physiological and psychological effects on humans, often inducing a state of relaxation and "biological rejuvenation." Scientifically, waterfalls are believed to be rich sources of "negative ions"—oxygen atoms with an extra electron—which are created by the high-energy collision of falling water. When these ions reach our bloodstream, they are thought to produce biochemical reactions that increase levels of serotonin, helping to alleviate stress, relieve depression, and boost daytime energy. Psychologically, the "white noise" of a waterfall acts as a natural sound mask, which can lower cortisol levels and calm the nervous system. The visual "fractal" patterns of moving water also engage the brain in a state of "soft fascination," allowing the mind to recover from the "directed attention fatigue" caused by modern urban environments and screen time. This combination of clean, oxygen-rich air and rhythmic sensory input is why "waterfalling" is often prescribed as a natural therapy for improving mood and overall mental health.