Roman exploitation of the countryside is symbolised by the Villa Romana del Casale (Sicily), the centre of the large estate upon which the rural economy of the Western Empire was based. The villa is one of the most luxurious of its kind. It is especially noteworthy for the richness and quality of the mosaics which decorate almost every room; they are the finest mosaics in situ anywhere in the Roman world
The UNESCO Committee decided to inscribe this property on the basis of criteria (i), (ii) and (iii), considering that the Villa del Casale in Piazza Armerina is the supreme example of a luxury Roman villa, which graphically expresses the predominant social and economic structure of its age. The mosaics that decorate it are exceptional for their artistic quality and invention as well as for their extent.
Source: https://whc.unesco.org/en/list/832/