Local people have long known that Konocti is riddled with natural caves. Although most of the natural caves collapsed or were filled in for safety in the early 20th century, persistent local belief holds that Konocti's central magma chamber is a vast, empty vertical cavern, partly filled with Clear Lake water and connecting with the lake via an underground seep. This cavern might be the largest on Earth, though its existence is difficult to prove due to the unstable and eroding structure of the volcano's cone. Heavy vegetation also conceals cave entrances. No accurate map or survey of the caves has been created due to the heavy underbrush and unstable hillsides. The majority of Konocti is owned by private parties, who have discouraged exploration and study of the mountain in recent years. The County of Lake recently purchased 1,520 acres on top of the mountain. As a result, Mt. Konocti County Park opened to the public on September 24, 2011.