Spanning a total water surface area of more than 210 km², Tam Giang - Cau Hai lagoon system,consisting of three main lagoons: Tam Giang, Thuy Tu, and Cau Hai, is often praised as a natural masterpiece bestowed upon Hue. The Tam Giang - Cau Hai lagoon system connects to the East Sea via the Thuan An inlet (Tam Giang lagoon) and the Tu Hien inlet (Cau Hai lagoon). It is the largest brackish lagoon system in Vietnam as well as all of Southeast Asia with an incredibly rich and diverse ecosystem.

Tam Giang - Cau Hai lagoon system is a world-class brackish water area. It is the largest in Southeast Asia, with special value in biological resources and countless gripping things in history and culture.... This area is seen as a "precious biological gem" that nature has bestowed on the ancient capital. With what existent, is it necessary to build an exhibition space or a museum for the Tam Giang - Cau Hai lagoon system?