Bich Dong - Tam Coc
Location: In the Ngu Nhac Son Mountains, in Dam Khe Village, Ninh Hai Commune, Hoa Lu District, Ninh Binh Province.
Characteristics: King Le Canh Hung said that Bich Dong was the second nicest grotto in Vietnam, after the Huong Tich Grotto in Ha Tay Province.