In 1773, Mr. Nguyen Nghiem (the father of the great writer Nguyen Du) visited this cave. After viewing the whole scenery of the mountains, waterways, fields, and sky covered in green mist, he gave the cave a very beautiful and romantic name, Bich Dong (which literally means “Green Pearl Grotto”). Bich Grotto is said to be the second most beautiful cave in Vietnam. The Bich Dong Pagoda was built near the cave in the Le Dynasty.
Bich Dong Pagoda, built on Ngu Nhac Mountain, is divided into three levels: Ha Pagoda (lower pagoda), Trung Pagoda (middle pagoda), and Thuong Pagoda (upper pagoda). On the mountain peak stands the statue of a scholar Mandarin looking at the horizon in hope of viewing the spectacular landscapes of Hoa Lu.

From the upper pagoda, one has the most magnificent view of Bich Dong, which is romantically charming in terms of architecture and history. The location for this pagoda was chosen in 1428 after two monks were charmed by the view of the river and the mountains. Later, King Le Canh Hung wrote a poem in honor of the beautiful pagoda and landscape. He was the one who said that Bich Dong Pagoda was the second nicest pagoda in Vietnam, after the Huong Pagoda (also called Perfume Pagoda) in Hatay Province.