Roof Top Cupola
The earlier cupolas that were atop the Cathedrals were larger than the ones we see today. The would normally have a balcony. The balcony is where they would announce daily prayer.
Cupolas also allowed the snow to fall off the roof in European states keeping the roof from caving. Most Islamic and European states you passed through during earlier times had cupolas scattered throughout the country. The cupola wasn’t introduced to America until 1815.