After a day of prayer at Mount Arafat, the site of Prophet Muhammad's last sermon 1400 years ago, a mass of pilgrims in white robes - meant to erase differences of class and culture - moved on foot chanting prayers.
Others climbed onto motorbikes, buses and whatever other means of transport they could find to take them to Muzdalifah, where Hajj tradition says they should spend the night.
On Tuesday, the Muslim Eid al-Adha holiday, the pilgrims must return to the Grand Mosque in Mecca and then complete three days of throwing stones in Mina at pillars on the spot where Islam says the devil appeared to biblical patriarch Abraham.
Suhaila Saad el-Din, 65, from Lebanon said, as she gathered her stones: "It feels as if I've finished the biggest part of haj. I'm grateful."
Some 250 pilgrims died in a 2004 stampede during the pillar-stoning. The government has re-organised access to the area and promised to remove pilgrim squatters who camp there.
Day of Arafat
Tracing a journey made by the Prophet Muhammad, pilgrims gathered on Monday for an emotional assembly in Arafat, a small plain 250m above sea level surrounded by mountains on all sides.
They prayed for mercy and forgiveness at the scene of the Prophet's last sermon.
The rite of wukuf, standing before sunset on Arafat, is the high point of the Hajj and without which it would be considered incomplete.
Prince Muhammad Bin Nayif Bin Abd al-Aziz, the Saudi deputy interior minister, said in a statement that more than 1.55 million foreign pilgrims of 177 nationalities are taking part, up 1.2% from the previous pilgrimage.
Major-General Mansur al-Turki, the Interior Ministry spokesman, said on Sunday: "This does not include Saudis, foreigners living in Saudi, and pilgrims coming on their own outside the tours."
Muslim pilgrims gather at the
Mount of Mercy (Jabal al-Rahma)
He suggested that an estimate of 2.5 million may be close.
He said the exact number would be known only on Tuesday when pilgrims return to Mina to perform the stoning of three pillars symbolising Satan's powers.
Al-Turki, using the Arabic for the pillars, said: "This year we drafted a special plan to channel pilgrims to jamarat."
In the aftermath of the death of 76 people on Thursday in the collapse of an ageing hostel in the heart of Makka, the Saudi official said the kingdom had prepared itself to deal with major potential emergencies during the Hajj including fires, stampedes, torrential rain, food poisoning, terror acts and even chemical attacks.
He said pedestrian traffic would move on three main roads while two new tunnels were added to transport pilgrims in buses to the area.
"We have specified in our plan 12 major emergencies that may occur during the Hajj"
General Adel Zamzami,
Civil Defence chief,
Almost 60,000 security, health, emergency and other personnel are involved in organising the Hajj this year, trying to make sure none of the deadly incidents that have marred it in recent years are repeated.
In addition, 14 hospitals and dozens of clinics and field facilities are ready to deal with any contingency.
General Adil Zamzami, the civil defence chief for the western region, said :"We have specified in our plan 12 major emergencies that may occur during the Hajj."
Hajj is one of the five pillars of Islam and a once-in-a-lifetime obligation for all devout, able-bodied Muslims with the means for the journey.