Click through to see photos from this year's Hajj pilgrimage:
Hajj
Each year millions of Muslims embark on the hajj pilgrimage to Mecca, Saudi Arabia, making it one of the largest pilgrimages in the world today. The five-day hajj pilgrimage takes place from eighth to the 12th of Dhul Hijjah, the final month of the Islamic lunar calendar. In 2012, the hajj pilgrimage is observed from Oct. 24th-29th.
Performing hajj is one of the five pillars of Islam. Able-bodied Muslims are obligated to perform Hajj at least once in their lifetime.
Tradition says the practice of hajj goes all the way back to Abraham. Millions of pilgrims walk from Mecca to Mina to the Plain of Arafat to stand near the Mount of Mercy and ask Allah for forgiveness. Pilgrims then walk back to Mina to throw pebbles at pilars that represent the temptations of Satan.
The symbolic animal slaughter of Eid al-Adha comes next, followed by a trip back to Mecca to perform tawaf, which is walking around the Kaaba, the most sacred site in Islam.
Pilgrims drink from a holy stream, the Zamzam, before returning to Medina to finish the hajj.
Below is a handy infographic courtesy of Al Arabiya to help understand the five steps of the Hajj pilgrimage.
To zoom in, click here.
Curious to see what the Hajj is like? YouTube is live-streaming the Hajj this year at www.youtube.com/makkahlive.
At HuffPost Religion, we're telling the news in photos. Click here to check out our photoblog.