Flying buttresses are architectural structures that support the walls of a building, particularly in Gothic architecture. They consist of arched supports that extend from the upper part of a wall to a separate, lower support structure. This design helps distribute the weight of the roof and walls, allowing for taller and more open interiors. These supports are often seen in famous cathedrals, such as Notre-Dame de Paris. By transferring the weight away from the walls, flying buttresses enable the use of large stained glass windows, which are a hallmark of Gothic cathedrals.