A blind window does not open. It is a formal window installation to create visual changes in the exterior of a building, not to provide lighting or ventilation. These windows date back to the late 17th to the mid-19th centuries when the window tax, a fixed property tax based on the number of windows, was established in several European countries. Many blind windows are the remnants of existing windows that were bricked up to evade taxes. Some blind windows are installed to decorate an expanse of exterior wall or to bring symmetry to a façade.