Next year, Việt Nam will celebrate National Tourism Year in Quảng Ninh. John Ball traces the origin of the province’s world famous Hạ Long Bay to a vast plain that embraced Việt Nam and Cambodia and spread all the way, like a giant tongue, down to the tip of Java. This land mass was known as Sundaland.

Until five or six thousand years ago, the Red River flowed through Hạ Long Bay, which was then dry land, and down through a vast fertile plain that ended near the tip of what is now Hainan Island. Most of this plain is now buried under the waters of the Gulf of Tonkin.

In those ancient times, the river flowed into a sea that was about 120 metres below its present level, like most seas and oceans around the world.

However, as the earth began warming 27,000 years ago at the end of the last ice age, seas around the world began rising gradually until they reached their present levels about 5,000 years ago. 

The inundation, part of a world event referred to in ancient Mesopotamian texts and the Bible, swamped a vast area of coastline around the world, particularly in South-east Asia and Australia to the South. This gave birth to oral histories still repeated by native people in Australia and New Guinea – and by all ethnic groups throughout Việt Nam. An article on the subject by the late ethnologist Đặng Nghiêm Vạn, The Flood Myth and Origin of Ethnic Groups in South-east Asia, was published in 1993.

Vạn, director of the Centre for Study of Religion and former vice-director of the Institute of Ethnology in Hà Nội, collected 300 stories of an ancient flood in his travels throughout Việt Nam. They were published by the American Folklore Society in its journal. Vạn, Việt Nam’s prominent historian and ethnologist, died in 2016.

Geologists today refer to the two pre-flood land masses as Sundaland (Southeast Asia) and Sahul (Australia, Tasmania and New Guinea).

Southeast Asia was then basically one large land mass stretching like a giant udder from what is now Thailand, Cambodia, Laos and Việt Nam to embrace Malaysia, Sumatra and most of the islands as far as Java.

It was a vast, fertile region fed by silt from rivers flowing for millenia from the slowly rising Himalayas – including the Red River and the Mekong. The rich plains, including what is today the Gulf of Tonkin, now home to Hạ Long Bay, are believed to have held a large population of Austronesian speaking people, including the small, dark Negritos who still remain in pockets throughout former Sundaland – and once even as far as the rainforests of northern Australia and Tasmania.

The seas rose slowly for thousands of years, but at times advanced quite rapidly, as the ice sheets around the world continued to melt. When the warming stopped, somewhere around 5,000 to 7,000 years ago, the shorelines of Asia, Australia and the world had altered dramatically. (Some argue that the warming is an “on-again off-again” work in progress, like even more ancient ice ages).

In the giant Sahul landmass, Australia was cut off from Tasmania and New Guinea, stranding people and animals such as the Tasmanian Tiger. In Sundaland, the solid land mass was broken into a patchwork of islands stretching from mainland Việt Nam, Cambodia, Thailand and Malaysia to Sumatra, Java and Borneo in Indonesia.  

Ancient: The Soi Nhụ Culture in adjacent Bái Tử Long Bay is a forerunner of the Vietnamese people. — VNA/VNS Photo Minh Đức

 The “world flood”, as it has been called, is believed to have slowly submerged Sundaland, a vast and fertile cradle of mankind that evolved after early people began a long journey out of Africa 60,000 to 100,000 years ago.

According to historians, the route they took was along the coast of the Middle East and India to Southeast Asia. Why? Because it was the simplest and safest way to migrate – and fishing mostly kept them alive. It is interesting to note that large conch shells were used by these ancient wanderers to communicate with each other along the shores. The conch is still a vibrant symbol in Asian cultures as far away as Tibet.

Some anthropologists believe that the flood led to forced migrations out of Sundaland into the hills and valleys of the Southeast Asia we know today. They compare the high genetic diversity of Southeast Asia to a comparable lack of diversity in northern Asia. In other words, the spread of the Sundaland peoples after the flood triggered the spread of people north into the Eurasian landmass.

The rising waters also isolated elephants, tigers and rhinoceros and even certain types of river fish, often leading to the evolution of a smaller species on smaller territory.