via Viet Nam Express, 07 October 2018:
Archeologists believe they have uncovered evidence that caves in northern Vietnam were home to prehistoric people 4,000 years ago.
Relics dating back to that time were found in three caves located in Chiem Hoa District, Tuyen Quang Province.Trinh Nang Chung of the Vietnam Institute of Archaeology led the excavations that led to the finding of relics in Pu Chua Cave of Minh Quang Commune and Ngan and Khi Caves of Phuc Son Commune last July.
Source: Prehistoric vestiges unearthed in Vietnam – VnExpress International
