Through their reports on recent archaeological excavations and geological research, speakers at the workshop said the site have special natural beauty and geological features while featuring heritage that helps paint a picture of how humans live in ancient times.

The workshop aims to build a scientific file on the historical and geological value of the site to submit to UNESCO for recognition as a mixed natural and cultural heritage site title.

According to Prof Paul Dingwall from the International Union for Conservation of Nature at UNESCO, the important thing is to prove that the distinguished value of site involves its scenery and environment. However, it is also necessary to show evidences that the site has experienced a complex process of geological development, he added.

Trang An was the site of Hoa Lu, the country's capital more than ten centuries ago, which should be mentioned in the file, Dingwall stressed.

Prof Richard Engelhardt from UNESCO's International Council on Monuments and Sites agreed that the file should mention that early communities living at the site had adapted well to the local environment during the most severe weather conditions.

It is a must to connect all the evidences to build a persuasive file, he said.

Pham Cao Phong, secretary general of the Vietnam National Committee for UNESCO, said the country has no officially recognised heritage site in terms of archaeology.

"The Trang An Tourism Complex is the first ever to be submitted to seek a mixed title," he said.

Dubbed "Ha Long Bay on land", the site covers an area of 10,000ha, including the three areas of the Trang An Ecological Site, Tam Coc-Bich Dong Site and Former Hoa Lu Former Capital Area. The region is scattered with karst topography such as limestone mountains, caves and lakes.

The site is home to diverse fauna and flora with 500 kinds of flora, 73 kinds of birds, 41 kinds of other animals. Scientists found traces of early people dating back 5,000-30,000 years ago in the nearby Boi and Trong caves.

Bui Van Thang, chairman of local People's Committee, confirmed that in the near future, the province will focus on preservation, restoration and effective exploitation of natural resources for tourism, which is a sustainable way of economic development.

The scientific file will be completed by September next year 2013 before being submitted to the UN cultural body together with a file on the Cat Ba Archipelago (for the title of Natural Heritage Site). The final result will be announced in 2014.