One of the main problems facing Saudi Arabia and many other countries in the region is the movement of sand, which threatens the urban areas.  With the expansion of new installations and other projects, sand dune movement is costing governments a lot of money and energy. We shall shed some light on this problem and introduce students to some basic knowledge about this issue. This knowledge will include information related to dune movement, factors affecting their movement, the stabilization of dunes, and different types and shapes of dunes. We investigate a particular type of sand dunes, the barchan sand dune, and analyze its geometry and how to approximate its volume and what parameters are needed. For this lesson, students should have a solid exposure to both three-dimensional geometry and single variable calculus. The lesson could be completed in a 45-50-minute class period.