Vernal Fall is a 317-foot (96.6 m) waterfall on the Merced River just downstream of Nevada Fall in Yosemite National Park, California. Like its upstream neighbor, Vernal Fall is clearly visible at a distance, from Glacier Point, as well as close up, along the Mist Trail. The waterfall flows all year long, although by the end of summer it is substantially reduced in volume and can split into multiple strands, rather than a single curtain of water. Swimming above Vernal Fall carries a great deal of risk: the rocks are slippery, the river has strong undercurrents that may not be visible from the surface, and tourists have been swept over the fall to their deaths. Though swimming there is illegal and warnings to stay out of the water are clearly posted, several deaths have occurred when visitors entered the water above the fall in the vicinity of the Silver Apron and Emerald Pool. Three people died in a single day, on July 19, 2011, after being swept over Vernal Fall in this manner. (Source: Wikipedia.org, CC BY-SA)