Over two million Muslims from around the world, including 87,000 Iranians, are now in Mecca, Saudi Arabia to participate in the annual pilgrimage of Hajj, one of the largest and most significant religious gatherings in the world. Our correspondent Gisoo Misha Ahmadi has traveled with these pilgrims and has explored the journey that millions of Muslims undertake each year, beginning with their arrival at the plain of Arafat.