A corner of Thi Nai Lagoon in Quy Nhon City, a popular beach city in Binh Dinh Province, south-central Vietnam. At one point, Thi Nai Lagoon acted as a marine base for soldiers from Tay Son. In late 2006, Binh Dinh inaugurated the Thi Nai Bridge, marking the longest cross-sea bridge in Vietnam at that time. “Quy Nhon City is the heart of Binh Dinh Province, while Thi Nai Lagoon will be considered the heart of the new Quy Nhon City,” Bao underlined. A design for the projected Thi Nai Lagoon urban area in Quy Nhon City, Binh Dinh Province, south-central Vietnam.