Hajj stampede: How to stay safe in mass gatherings

Story highlights

  • Hundreds killed Thursday in stampede at Hajj pilgrimage
  • Juliette Kayyem: There's a science to staying safe in large groups

Juliette Kayyem, a CNN national security analyst, is a professor at Harvard's Kennedy School of Government, a former assistant secretary in the U.S. Department of Homeland Security and founder of Kayyem Solutions, a security consulting firm. She also is the host of the Security Mom podcast. The opinions expressed in this commentary are hers.

(CNN)The images flooding in of Thursday morning's stampede in Saudi Arabia tell a horrifying tale. Hundreds of people have suffered a gruesome death as they were crushed or trampled during a stampede that occurred at the annual pilgrimage of devout Muslims to their holy city of Mecca.

The stunning toll is even more outrageous when y