Dioramas are widely used in the American educational system, mostly in elementary and middle schools. They are often made to represent historical events, ecological biomes, cultural scenes, or to visually depict literature. They are usually made from a shoebox and contain a trompe-l'œil in the background contrasted with two or three-dimensional models in the foreground. In California elementary schools, a popular assignment has fourth graders making a Spanish mission diorama to learn about the California Spanish missions.