Samarra: Shia pilgrimage centre

BACK IN FEBUARY 22, 2006, the rifts widened dramatically.

A bomb attack in Iraq has badly damaged one of the holiest sites in Shia Islam, sparking furious protests

They travel to the city to worship at the sacred tombs of Ali al-Hadi and al-Hasan al-Askari, the 10th and 11th Shia Imams, and the site where the 12th Imam, Mohammed al-Mahdi, disappeared.

Imam al-Mahdi, known as the "hidden Imam", was the son and grandson of the two previous imams, and Shias pray at the mosque for his return.

Shia Islam was led by imams, believed to be divinely appointed from the Prophet Muhammad's family, until the late 9th Century.

The huge complex also contains a second shrine above the cave (sirdab), where the young Imam al-Mahdi, Al-Askari's son, was said to have been hidden before he disappeared in 878.

Shia Muslims believe he did not die and still await his return more than 1,100 years later.

The other three major Shia shrines in Iraq are Najaf, Karbala and Kadhimiya in Baghdad.