Around 2.5 million or more Muslims from all over the world have headed to Saudi Arabia. Under heightened monitoring by some 20,000 medical staff and more than 100,000 security personnel, the world’s largest annual Islamic pilgrimage Hajj is taking place from November 25 to 29 in western Saudi Arabia in the holy cities of Mecca and Medina.

A Saudi man, wearing a mask for protection against swine flu, walks past Turkish and Iranian Muslim pilgrims at Jeddah airport upon their arrival in the Saudi Red Sea port city for the annual pilgrimage to nearby Mecca.