The Ornamental Buildings, as the name implies, serve only decorative purposes and the player can use them to beautify cities. Unlike previous installments of the series (most prominently Anno 2070), most ornamental buildings are available to the player from the start. Additional temperate fountains and the moon ornamental buildings are acquired by finishing some Sector Projects.
Update 1.7 added two new ornaments buildings which must be unlocked via a few short new assignments.