Hoa Lu: the remains are the temples dedicated to King Dinh and King Le, the two heroes who lived in 10th century and chose Hoa Lu to build the citadel of the capital city ( from 968 to 1009)
Trang An:Trang An grottoes whichis a gathering of 31 valleys, 50 cross-water caves, and home to 600 kinds of flora and over 200 kinds of fauna, many of them in the Red Book of Vietnam.
In 968, Dinh Bo Linh declared himself as the King. Since then Hoa Lu existed as the capital for the next 41 years (968 – 1009), of which 12 years was under the Dinh dynasty – King Dinh Tien Hoang, the country named Dai Co Viet, and 29 years later was under the Le dynasty – King Le Dai Hanh.
In 1010, King Ly Thai To moved the capital from Hoa Lu to Thang Long – present day Hanoi. Hoa Lu became the old citadel.