The Key Monastery is the brand ambassador of Spiti Valley, it is by far the biggest monastery in the valley, situated near the Spiti river on a hillside. Built about thousands of years ago, the need for a monastery arose when the Tibetian Buddhism started spreading in the valley. The monastery has a labyrinth, with interconnected dark rooms through the dark and narrow alleyways. The monastery holds a rich library of Buddhist sacred texts and manuscripts. The archaeological survey of India has kept a detailed list of all the assets of the monastery post-independence. It also has a wide array of medieval weapons stored inside it. Used in the old days to ward off attacks from dacoits and expeditionary forces. The people around the monastery would get inside and then, the monks would throw stones at the invaders to fend themselves. The Dhankar Fort and monastery also had the same response in times of disturbance. Another use of the weapons was to keep the subjects under control, as peaceful as it may look now, Spiti has had its fair share of bloodshed in the past. The kingdoms of Bushahr, Kullu, and Ladakh would constantly attack the area which was under the Nono of Spiti. The Mongols would also at times create unrest.