The city of Samarra is situated on the bank of the river Tigris some sixty miles from the city of Baghdad. The city is of outstanding importance because of its two shrines. Beneath the golden dome are four graves, those of Imam Ali Al-Naqi (10th Imam) peace be up on him and his son, Imam Hasan Al-Askari (11th Imam) peace be up on him. The other two are of Hakimah Khatoon, the sister of Imam Ali Al-Naqi who has related at length the circumstances of the birth of Imam Al-Mahdi (as) and the fourth grave is of Nargis Khatoon, the mother of Imam Al-Mahdi (as), peace be upon him. The second shrine marks the place where Imam Al-Mahdi (as) went into concealment. It has a dome that is distinguished for the soft delicate design that is worked in blue tiles, and beneath it is the Sardab (cellar) where the Imam is said to have disappeared.