Magnificent Coca Castle was built in the 15th century by Alonso de Fonseca, a mighty archbishop of Seville, during the reign of King Enrique IV of Castile. It's made up of two square baileys separated by a passageway. Both show polygonal towers at the corners. The double walls are 2.5 m thick and it's circled by a deep dry moat.
Coca castle is a mixture of western and Moorish military architecture, as can be seen from its decoration. It has a square ground plan, a moat and two walled enclosures, which gives it the air of impregnability for which it has been known over the centuries. The keep is located in the second area. It is made of brick and its walls are profusely decorated. The interior is very luxurious and lavish, and conserves its Mudejar decoration. Due to its great splendour, it was used more as a palace than as a fortress. It is one of the crowning works of the military Mudejar style.
The castle is owned by the Alva family and now serves as a training center for foresters. Their school is situated in the inner bailey.
The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.