The Diamond-Square algorithm is a method used in computer graphics to generate realistic terrain. It works by recursively subdividing a square grid and applying random height variations to create a more natural landscape. The process begins with a single square, where the corners are assigned initial height values, and then the center point is calculated using the average of the corners plus a random offset. This technique is particularly useful in creating fractal landscapes, as it produces a variety of terrains with mountains, valleys, and plains. The algorithm is efficient and can be implemented in various programming environments, making it popular among game developers and simulation designers.