(March 26, 2007) In the summer of 2006, as the Iranian-backed Hezbollah fought off Israelis in Lebanon and President Mahmoud Ahmadinejad faced down President George Bush at the United Nations, a bus full of Iranian pilgrims left Tehran on a journey to the holy city of Karbala, deep inside a shattered Iraq.

A roundup of links to local stories of global importance from around the world.

A round up of links to local stories of global importance from around the world.

Link to more information on Sunnia and Shia Islam.

Globally, the Shia account for an estimated 10 or 15 percent of the Muslim population, but in the Middle East their numbers are much higher: they dominate the population of Iran, compose a majority in Iraq, and are significant minorities in other nations.

The Shia rejected the authority of the Umayyad dynasty, claiming that the Umayyads were usurpers and demanding that leadership go to the direct descendants of the Prophet. The Shia rose in the city of al-Kufah (south of Karbala, in present-day Iraq) and, in 680 A.D., invited Ali's son Hussein to join them and be their leader.

March 20, 2007: Vali Nasr, Professor, U.S. Naval Postgraduate School, and author of THE SHIA REVIVAL, discusses Iran's emerging regional role and the escalating tensions between Iran and the United States with anchor Daljit Dhaliwal.

Pilgrims travel to Karbala year-round to honor Hussein, the martyred grandson of the Prophet Muhammad, whose murder, in part, caused the schism between the Sunni and Shia. In the time of Saddam such observances were banned, but in wartime Iraq, marked by vicious sectarian violence, the pilgrimage is more dangerous than it has been in years.

Learn where Sunni and Shia Muslims live with this map of the Islamic world.

Map of Shia holy sites.