In architecture, a cupola is a relatively small, most often dome-like, tall structure on top of a building. Often used to provide a lookout or to admit light and air, it usually crowns a larger roof or dome.
The cupola evolved during the Renaissance from the older oculus. Being weatherproof, the cupola was better suited to the wetter climates of northern Europe. The chhatri, seen in Indian architecture, fits the definition of a cupola when it is used atop a larger structure.
Cupolas can also appear as small buildings in their own right.
Cupolas on the towers of Montefiascone Cathedral, Italy.
Ribbed cupola crowns the minaret of the Mosque of Uqba, in Kairouan, Tunisia.
Inside of Armenian Orthodox church cupola in Lviv, Ukraine.
Cupolas were also used on some old barns for ventilation.
View from the interior of Cupola module on the International Space Station.
A cupola-style caboose with an "angel seat" above