North of Smolenice is the village Buková with water reservoir and a marked route, which leads southward to the romantic ruins of the Castle Ostrý Kameň from the 13th century. The Castle was a royal border fort guarding the Czech road in the past. It is in decay since the 18th century though part of its walls, bastion, and adjacent buildings are still observable. The top of the Castle provides a nice view of the Malé Karpaty Mts. and the Záhorská nížina lowland.
References: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.