Hundreds of thousands of Muslims are arriving in Saudi Arabia to take part in this year's hajj pilgrimage.
The five-day pilgrimage is one of the pillars of Islam and is expected of able-bodied Muslims - of both Sunni and Shi'ite sects - at least one in their lifetime.
The event, expected to fall from 13- 18 October this year, combines piety and passion and sees 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 pillars that represent the temptations of Satan.
The ritual re-enacts the prophet Abraham's experience when the devil confronted him in the desert, tempting him not to sacrifice his son as Allah had instructed.
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.
Scroll down for pictures from last year's hajj
A ring-shaped structure around the Kaaba enables elderly pilgrims and those with disabilities to perform the ritual with greater ease.
Pilgrims drink from a holy stream, the Zamzam, before returning to Medina to finish the hajj.
The days of Hajj have come. Allah accept the journey of all those taking this journey on and return them safely to their families. #Hajj2013-- Hussain Kamani (@HussainKamani) September 24, 2013
You may lose Wealth going for Hajj, but you'll InshaAllah come back Richest of the Rich in Good Deeds and Mercy of Allah!-- wakeuptoislam.co.uk (@wakeuptoislam) October 1, 2013
Nothing's worse than someone who live tweets their Hajj experience. Put your phone away & concentrate pls-- AlhamdulillahAlways (@deenhigh) October 1, 2013