Sufism is a mystical form of Islam, a school of thought that promotes introspection, spiritual intimacy with God, and rejects materialism. It has given birth to some of the world's greatest treasured works of literature, art, and music. Its current supporters value tolerance and pluralism, traits that startle fundamentalists in many religions. However, Sufism has been targeted in the past years. Militants attack Sufi mosques, killing a large number of people. Sunni radicals have carried out many attacks on Sufi shrines in Pakistan (while some Sufis are Shiites, the great majority are Sunnis).