China, Crescent Lake in the Singing Sand Dune

Crescent Lake, a natural wonder in the Gobi Desert, is renowned for its crescent shape and clear waters. Historically visited by explorers like Mildred Cable and Francesca French, the lake is a result of a natural wind-created depression. Despite low precipitation, it remains unburied due to unique geographical features. Legends speak of treasures like Iron back Fish and seven Stars Grass. The nearby Singing Sand Dunes produce musical sounds when disturbed, adding to the area's allure.

What role did Mildred Cable and Francesca French play in the history of Crescent Lake?

How does the Singing Sand Dune create sounds, and what is the nature of these sounds?