It was built in 11th Century.
It’s situated at the foot of Sai Son Mountain in Phuong Cach Commune, Quoc Oai District, Ha Tay Province, 30km southwest of Hanoi City, about 2 hours in motorbike.
You can reach it reserving a motorbike with a driver in a travel agency of Hanoi.
Behind the theatre, at the top of a mountain, there’s a wonderful temple where buddhist women sing religious songs.
You can hear one of these songs in the video.