A diorama is a model representing a scene with three-dimensional figures, either in miniature or as a large-scale museum exhibit. The word diorama can either refer to a 19th-century mobile theatre device or in modern usage, a three-dimensional full-size or miniature model, sometimes enclosed in a glass showcase for a museum. Dioramas are often built by hobbyists as part of related hobbies such as military vehicle modeling, miniature figure modeling, or aircraft modeling.