The Singing Barchan (Akkum-Kalkan) is a150-meter-high, 3-km-long sand dune in Kazakhstan's Altyn-Emel National Park, about 300 km from Almaty, famous for producing a loud, organ-like humming sound in dry weather. Located between the Big and Small Kalkan mountains near the Ili River, this natural phenomenon occurs when sand particles vibrate due to friction.
