Over 2 million Muslims from around the world are beginning the five-day hajj pilgrimage on Friday. They will circle Islam’s most sacred site, the cube-shaped Kaaba in Mecca, and take part in a series of rituals intended to bring about greater humility and unity among Muslims. The hajj this year comes at a time of heightened sectarian and political tensions in the Persian Gulf and as Muslim minorities in China, Myanmar, India, New Zealand and other countries face increased threats, even attacks. Here’s a look at the pilgrimage and what it means for Muslims: