Cupolas are ornamental domed structures located at the heights of pre-existing roofs or domes. The word "cupola" comes from the Latin word "cupo", which means "little dome".
Cupolas have both functional and aesthetic value. Roof cupolas provide a means for ventilation, and may provide a scenic view of the surrounding area. Such a cupola is also known as a belvedere, or a widow's walk, provided that it can be reached by a stair case from the interior of a building. The use of lighting, or a lantern is often employed in the cupola.
Cupolas have been appreciated for both their architectural beauty and functionality, and used throughout the prominent architectural periods, such as the Classical, Renaissance, and Georgian eras. Cupolas are also currently employed in revival architecture. Renaissance roof cupolas were among the most ornate, and most frequently graced the heights of cathedrals and churches. The interiors of the cathedral cupolas were often elaborately decorated with dramatic lighting and frescoes depicting religious scenes.
Barn cupolas were originally intended to provide ventilation. The cupola helped to circulate air through hay stored at the top of the barn, keeping the bales dry.