Fourteen centuries of religious schism within Islam has reached critical mass in the bitter, sometimes violent rivalry between Sunni-dominated Saudi Arabia and Shiite Iran. Here are five flash points in their hatred.
Iranian protesters overrun Saudi embassy, set fires
Flames rise from Saudi Arabia's embassy during a demonstration in Tehran. Iranian protesters stormed the Saudi Embassy in Tehran early on Sunday morning as Shi'ite Muslim Iran reacted with fury to Saudi Arabia's execution of a prominent Shi'ite cleric.