The Familiar but Beautiful Architecture of the Cathedral of Tarragona - Spain / by JD Andrews

The Tarragona Cathedral

The main gate is surmounted by a large rose window, similar to that in the Monastery of Sant Cugat or in the Cathedral of Majorca. The twelve spokes represent the twelve tribes of Israel, or the apostles. It has a diameter of 11 meters. The two lateral portal have also smaller rose windows.

~Wikipedia