Leland W. Sprinkle created the Great Stalacpipe Organ over three years by finding and shaving appropriate stalactites to produce specific notes. He then wired a mallet for each stalactite that is activated by pressing an associated key on the instrument's keyboard. The stalactites are distributed through approximately 3.5 acres (14,000 m ) of the caverns but can be heard anywhere within its 64-acre (260,000 m ) confines.