A stampede at the "stoning the devil" ritual has become the hajj pilgrimage's worst disaster in a decade. Saudi authorities say at least 717 people were killed; previous reports said at least another 450 were injured in the crush of people at Mina, near the holy city of Mecca, the AP reports. The BBC explains that the hajj is "the fifth and final pillar of Islam"; every adult Muslim who can physically and financially manage to do so is expected to make the pilgrimage once in their lives. Two million people are this year participating in the annual five-day pilgrimage, which started Tuesday. One of the final major rites of the hajj involves casting stones at pillars that signify the devil.
After numerous similar disasters at the ritual, including a 2006 stampede that killed 345 people, the Saudis spent $1.2 billion on measures to reduce congestion at the site where pilgrims hurl stones at three pillars, CNN reports. Read about other hajj-related tragedies, the worst of which happened in 1990, here. (Read more Hajj stories.)