The stamps feature the site's beautiful landscape and traditional local ceremonies. 

The stamps will be used in post offices throughout the country until December 31, 2016.

In UNESCO's words, "Trang An is a resplendent complex of limestone karst peaks which are permeated with valleys, including submerged ones, and surrounded by steep, almost vertical cliffs", nestling on the southern shore of the Red River Delta. 

Archaeological traces of human activity dating back thousands of years have been found within the complex. 

The Trang An Complex boasts several nationally recognised sites like the Trang An ecotourism site and Hoa Lu, Vietnam's capital in the 10th and 11th centuries. 

The area also has many other temples, pagodas, paddy fields, villages, and other sacred sites. 

It is home to around 500 flora species, 73 species of birds and 41 species of other animals, and has a diverse ecosystem with unique geological characteristics.