[Singing sands] at times fill the air with the sounds of all kinds of musical instruments, and also of drums and the clash of arms—Marco Polo, 13th Century Explorer
Certain sand dunes, particularly when disturbed, will occasionally emit a loud, low-pitch rumble that lasts up to 15 minutes and can be heard up to 6 miles (10 kilometers) away. Some dunes are known to do it regularly, even daily. The sounds have been variously described as roaring or booming, singing and musical (e.g., kettle drum, zither, tambourine, bass violin, and a trumpet). They have also been compared with the sound of a foghorn or low-flying propeller-driven aircraft . You can listen to them here, or here.
This phenomenon was reported from the Middle East for more than 1500 years and appears in Chinese literature from as early as the ninth century. Marco Polo was convinced that evil spirits caused them.
