Please note that the content of this book mainly consists of articles that are available from Wikipedia or other free online sources. Theater curtains and stage drapes are pieces of fabric that completely or partially cover a stage. They come in many different types. The front curtain, also known as the main curtain, act curtain, house curtain, or main drapery, hangs behind the proscenium arch. It is usually made of heavy material, as its purpose is to conceal the stage and dampen sound. In smaller theaters, they typically consist of two curtains that open horizontally, known as a traveler. In larger theaters, they usually open vertically and disappear from view into the fly tower. This type of opening is referred to as a guillotine opening, named after the famous execution device. A single curtain that moves horizontally across the entire opening is called a tab curtain.