The lake was discovered in 1905 by a thirteen-year-old boy named Ben Sands. As the story goes Sands, who often played in the cave, happened upon a small opening and crawled through. The room was so large he was unable to see the ends of the room with his lantern, so he threw balls of mud in all directions and heard splashes.
When he went back home and told people of his discovery they were hesitant to believe him. By the time Ben convinced his father to go back down with him to explore it further, the water level had risen, hiding the cave entrance from them. It was rediscovered by local explorers several years later.
The visible surface of the lake measures 800 feet (240 m) long and 220 feet (67 m) wide (4.5 acres (1.8 ha)) at normal "full" capacity. Cave divers have explored several rooms that are completely filled with water, without reaching the end of the cave. This exploration was conducted in the 1970s.
For many years The Lost Sea was considered the world's largest underground lake and is still recognized as the world's second largest non-subglacial underground lake after Dragon's Breath Cave, Namibia.
According to wikipedia
