Another unique wonder of nature is the Singing Sands, 182 km northeast of Almaty, on the right bank of the Ili River. In dry weather this sand-dune emits a sound like an organ playing. The Singing Sands make an unforgettable impression. The humming and vibration are caused by the scarcely perceptible movement of sand sliding down the slope. The friction caused by the movement of the dry grains of sand, combined with the dry air, electrifies them, causing the vibration. Because of the surrounding favourable resonant conditions, powerful sound waves are produced which, bouncing off the solid ground, also cause the dune to vibrate. The sound can be heard from several kilometres away. The dune does not "sing" in wet weather.
    There are two sandstone hills,big and Little Kalkan, which are over 120 m high and 4 km long. Despite the looseness of the sand and the strong winds, the singing dune does not move around the plain but has remained in the same place for millennia. Its south-western slope is smooth while the opposite north-eastern side has several ridges with gentle inclines.
    The dune has a sharp ridge with several protruding peaks, so it is actually possible to ski down it.