Located 8km northeast of Quy Nhon city, Thi Nai lagoon is the largest lagoon in Binh Dinh with a rich ecosystem with many precious flora and fauna and many beautiful landscapes that are very attractive to tourists. Thi Nai lagoon covers an area of ​​​​over 5,000 hectares of water surface, runs for more than 10 kilometers, and is nearly four kilometers wide. This place has valuable resources given by nature, and is a hiding place for biodiversity with a rich mangrove ecosystem: in which there are 25 species of seagrass; fauna has 64 species of plankton, 76 species of fish; there are hundreds of species of birds, of which 23 species belong to the group of waterfowl and migratory birds, 10 kinds of forest birds.... In the lagoon, near the west bank, there is a small mountain - on which there is a small temple established by fishermen to worship the water god - the shape of the mountain resembles an ancient tower, called the Fortune Teller Tower, making the lagoon landscape more vivid and attractive. Every morning, the evenings of the full moon are submerged in the lush green mangroves, the surface of the lagoon is blurred and fanciful like a fairyland.
Historically, Thi Nai lagoon was the naval base of the Tay Son Dynasty, where fierce naval battles took place between the Tay Son insurgent army and Nguyen Anh's army in the early 19th century (in 1801).

Located to the east of Thi Nai lagoon, like a giant screen facing the sea for Quy Nhon city is Phuong Mai peninsula, with a system of overlapping rocky mountains and huge sand dunes, stretching to the sea for about approx 15 km. North of the peninsula and to the northwest are beautiful beaches stretching for tens of kilometers. From a distance, Phuong Mai peninsula looks like a dragon's head, its body stretches north to the De Gi gate. At the southern end of the peninsula is a lance-shaped blade with many interesting and dangerous rock holes, which swiftlets often pull back to make nests, offering mankind a rare and nutritious "salanganes' nest" specialty. .
In harmony with the natural beauty of Thi Nai lagoon - Phuong Mai island is Quy Nhon - Nhon Hoi bridge and road project with a total length of more than 7km including 5 short bridges and Thi Nai bridge. In particular, the most prominent is Thi Nai Bridge with a length of 2,477.3m, this is the longest sea-crossing bridge in Vietnam with 54 spans connecting Quy Nhon city and Nhon Hoi economic zone. Thi Nai Bridge is not only the pride of the people of the Land of Martial Arts, but also a highlight that attracts many tourists when coming to Ho Chi Minh City. Quy Nhon.