The online petrography atlas offers a wide range of explanatory diagrams and photomicrographs (currently more than 800 images) covering an extensive spectrum of carbonate textures, grain types, diagenetic features, depositional environments and case studies. Carbonateworld website aims to facilitate the undergraduate and postgraduate learning of carbonate microfacies. It is designed to provide on-line exercises to test the acquired familiarity with petrographic description of carbonate rocks.