Sheck Exley was a pioneering cave diver who made significant contributions to the sport. He was the first to log over a thousand cave dives in less than seven years. Exley invented essential diving equipment, including the redundant second-stage regulator, and advanced safety techniques for cave diving. His deep dives in the late 1980s remain impressive even today. We honor his legacy and contributions to the diving community, which continue to influence how divers explore underwater caves.