10/26/2012 12:45 pm ET Updated Dec 26, 2012

The Hajj Explained: A Look Into Islam's Holy Pilgrimage (VIDEO)

Millions of pilgrims are arriving in Mecca for Islam's annual Hajj pilgrimage that began on Wednesday, a journey all Muslims must perform at least once in their lifetime, if they are able to make the expensive, difficult journey.

To give you a sense of what it entails, here is a feed of the Makkah Live Stream channel on YouTube.

The pilgrimage is a duty for both Sunnis and Shias, yet it comes at a time when tensions in the Muslim world are running high over the conflict in Syria that has killed more than 30,000, and has divided Muslims all over the globe.

Despite a call from Saudi Arabia's top cleric for unity and a pilgrimage free from nationalist sentiment, Syrian pilgrims have raised rebel flags as they participate in the holy ritual.

I was joined by Dena Takruri, HuffPost Live Producer, and Reverend Paul Raushenbush, HuffPost Senior Religion Editor; Zuleqa Husain, Al Jazeera English Producer; Ebrahim Moosa, Professor of Islamic Studies at Duke University; Najeeba Syeed Miller, Assistant Professor at the Claremont School of Theology; and Qasim Rashid, Author of the upcoming book "The Wrong Kind of Muslim."

Click through to see photos from this year's Hajj pilgrimage: