The International Union of Geological Sciences (IUGS) has recognised Hạ Long Bay - Cát Bà Archipelago in the northern province of Quảng Ninh and neighbouring Hải Phòng City as a world geological heritage site, Associate Professor Dr Trần Tân Văn, former Director of the Vietnam Institute of Geosciences and Mineral Resources under the Ministry of Natural Resources and Environment (MoNRE), said on August 25.