Los Arcos Castle was built around 1474. The square form castle has four corner towers and it was surrounded by a moat. It was built of masonry, dressed stone and brick, as a rectangular enclosure with squat towers at the corners and a keep in the centre. It is not open to visits at the present as it is private property and currently inhabited.
Near the castle they have found the remains of an old Gothic-Mudejar hermitage or basilica and the medieval Castillejo bridge.
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.