Trang An ecological ecological area in the south of Hoa Lu ancient capital converges many water caves on an area of ​​hundreds of hectares. This is known as the Halong Bay on land of Ninh Binh. Trang An ecological activity complex is located in Truong Yen, Ninh Xuan and Ninh Hai communes (Hoa Lu district), Gia Sinh commune (Gia Vien district), Ninh Nhat commune, Tan Thanh ward (Ninh Binh town), with An area of ​​over 1500 hectares was discovered several years ago. In 2001, the cave area was systematically discovered thanks to the research works of scientists and indigenous people. This is a very attractive tourist address. Visiting Trang An hydroelectric cave, guests can follow the normal waterway. There are about 50 dry caves and 50 water caves.

       The caves are connected by nearly thirty valleys, each of which is a water-color painting, the widest being Tran temple valley (241,600 m2). The valleys are connected by cross-water caves that make the mountains stick together, creating a lively appearance. Sparkling stalactites, flowing down the walls of the cave, create vivid wonders. The name of the cave, the cave with ancient massage, all evoke periodic historical stories: Seo Lon cave, Si cave, Ao Trai cave, Thuoc cave, Sinh cave, Cooking Wine, Dia Linh cave, Ba Giot cave, Sang cave, Dark cave , May cloud, Khong valley ...

       The length of the caves here adds up to nearly 20 km. On the tour, visitors will stop at the historic sites bearing the imprints of Dinh-Le-Ly dynasties such as Lang valley (after the reign of King Dinh), Tran temple (worshiping Hung Dao Dai Vuong), Khong government (worshiping of the seven mandarins) Dinh), Bai Dinh pagoda, hidden Long cave, Ban Long pagoda ... During the process of exploitation, archaeologists have discovered many artifacts such as: disc, coffin, pottery, pottery, ancient money, worship tower, Buddha, porcelain bowl, horse music. ... (of the 10th century).
  
       In particular, the mountain ranges here exist a diverse and rich ecosystem, including rare animals such as: phoenix, flute, jumps, monkeys, pythons, especially the white-cheeked gibbon, a species named in the world red book. In 2001, Ninh Binh has zoned protection and built Trang An into a key tourist destination. In the development plan, Trang An eco-tourism site has nine waterways. On each stage, visitors will be stopping at different attractions such as: sightseeing temples, ancient pagodas, historical sites; relax, visit eco-islands. In particular, there will be 12 islands named twelve, arranged in a circle. On the main islands are beautiful parks, surrounding the cave area will be a stream
river with rich natural ecosystems. It is planned to build a temple on Bai Dinh mountain (Gia Sinh commune, Gia Vien district). Legend has it that Zen Master Nguyen Minh Khong, when he came to this mountain to search for medicine, discovered the cave and turned it into a place of Buddha worship. This is also the place where King Quang Trung chose to set up a festival before marching to liberate Thang Long. Within the temple grounds are three bronze Buddha statues, each weighing more than 50 tons, along with 500 stone Han statues on the mountains.