Mazari Sharif is the fourth largest city of Afghanistan. It is the capital of Balkh province and is linked by roads to Kabul in the south-east, Herat to the west and Uzbekistan to the north. Mazari Sharif means "Noble Shrine," a reference to the large, blue-tiled sanctuary and mosque in the center of the city. Most Afghans (both Shia and Sunni) believe that it is the tomb of Ali ibn Abi Talib, the Prophet Mohammad's son-in-law and cousin, and fourth Kalif of Islam.