These are skylights in the four corner buildings of the mosque in the palace gardens in Schwetzingen, Germany. These are not proper skylights but fake windows in the dome of the roofs, showing different phases of the moon: quarter, half, three quarters and full moon. The Red Mosque was never intended as a place of worship but is considered a “folly” – a building which served no purpose but to be there and be beautiful. It was constructed at the end of the 18th century when all things Turkish were very fashionable. It combines elements of Eastern and Western architecture.