Situated on Lombo Island, it is 2km away from Sungsot Cave. Access to the entrance of the grotto is on the Catba – Haiphong sea passage. The exit leads to a ‘garden’ area outside the grotto. Mecung is one of grottoes containing archaeological remains of Halong Culture dating from 20,000 years ago. In the entrance, visitors can see, to a thickness of 2 –3 m, cultural deposits of ancient freshwater shells – evidence of the pre-historic people who used to live in the grotto.