Fujichrome 100, OM-2S, 24mm lens, 1/60 second at f/2.8, T32 electronic flash, tripod.
"Into this small hole drains the entire volume of Hawkins River . I wanted to see what lay below, so I thought I'd better take a snapshot for posterity in case I couldn't get back up. Very cold! I don't think anyone had ever been down there before..."