The Château de Calmont d'Olt is perched atop a basalt dyke. It provides a panoramic view of the Aubrac highlands.
Flint fragments and a polished stone axe are evidence of occupation of the site for 5,000 years. The ministerium Calvomantese was first mentioned in 883, in documents from the Abbey at Conques. It has always had a military significance, commanding the road from Rodez to Aubrac and, more widely, the crossing of the River Lot on the Toulouse-Lyon route. The building of the castle was begun in the 11th century built and continued until the Hundred Years' War with the building of a second curtain with eight towers in 1400. Beyond this date, there was no further development. Abandoned by its owners in the 16th century, the castle fell to ruin. The castle, in its present state, is an important milestone in the history of castle building in medieval Rouergue. It bears witness to the architectural adaptations of castles to the technical progress of the Hundred Years' War.
The castle is part of the Route des Seigneurs du Rouergue (Route of the Lords of Rouergue) which groups 23 castles.
The site highlights the theme of siege warfare. Full-scale war machines have been reconstructed and visitors may assist in the launching of projectiles with. There is a siege tower from the 15th century with bombards, trébuchets from the 14th century and pierrière from the siege of Toulouse from the 13th century. Visitors are also invited to take part in other demonstrations including archery, fencing and making chain mail.
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.