Halong Bay is made up of over 3000 limestone karsts that soar skyward out of calm emerald waters. Within the islands of the Bay there are hundreds of beautiful caves, including many famous names such as Thien Cung, Dau Go, Sung Sot, Tam Cung and Bo Nau. Some of them are archaeological sites retaining tangible archaeological evidence of Soi Nhu and Ha Long prehistoric cultures such as Soi Nhu, Me Cung, Tien Ong, Thien Long, Hang Trong, and Trinh Nu caves.