MECCA, Saudi Arabia (CNN) -- The annual Islamic Hajj pilgrimage commenced formally in Mecca on Wednesday.
The Hajj is expected to attract three million Muslims across the world this year, up 500,000 from last year.
Some pilgrims have traveled to Masjid Al Haram since Tuesday afternoon, walking around Kaaba, a cuboid building which is in the Masjid Al Haram and regarded as Islam's most sacred site, in a counter-clockwise direction.
Among the five pillars of Islam, the Hajj is required of all able-bodied Muslims at least once in their lifetime.