After sunrise on the ninth of the Islamic month of Dhu Al-Hajjah, this vast crowd of nearly two million begins to walk some eight miles to the Plain of Arafat, passing Muzdalifah on the way. Many perform the noon and afternoon prayers at the Nimerah Mosque, a tradition set by the Prophet.
Approaching Arafat by midmorning, the pilgrim is amazed to find the vast plain covered by what appears to be a thick fog, even though the temperature hovers around 90 degrees Fahrenheit. This optical illusion is created by thousands of sprinklers placed atop 30-foot poles and spaced some 50 feet apart, which spread a fine mist of water to provide coolness. Millions of containers of chilled water are distributed from refrigerated trucks located along the pilgrim route.
Despite these precautions, the wail of sirens is ever present as hundreds of ambulances pick up pilgrims suffering from heat exhaustion and transport them to special clinics for treatment. The more serious cases are evacuated by helicopter to hospitals.
Pilgrims are required to spend the day in the plain, performing what is called the Standing at Arafat. Here they also visit the Mount of Mercy and ask for God's forgiveness for any sins committed and for blessings. Facilities have also been set up here to feed the pilgrims and meet any requirement they may have.
After the sun has set this river of humanity retraces its steps back toward Makkah, but stops at Muzdalifah until the brightness of day appears on the eastern horizon. Here the pilgrims collect seven pebbles and carry them to Mina. As they arrive in the valley, they trek along a two-level pedestrian walkway some 100-yards wide toward the three stone pillars called the Jamarat, which are meant to represent Satan. The pilgrims are required to cast the pebbles they have collected at the Stone Pillar of Aqabah while praising God, in a symbolic rejection of Satan. As the pilgrims approach along the walkway, they join those already at the pillar and, after hurling their pebbles circle toward the exit ramp in the direction of Makkah. Signs in various major languages direct the crowds along the route.
The pilgrims then walk some four miles along pedestrian walkways to reach Makkah, where they perform the tawaf, circling the Ka'abah in the Holy Mosque seven times counter clockwise. They then perform sa'ay, the running between Safa and Marwa in an enclosed, air-conditioned structure. Male pilgrims are then required to shave their heads, although cutting a lock of hair is acceptable for both men and women. At this point the pilgrims sacrifice an animal, donating its meat to the needy. Each year, over 600,000 animals are sacrificed, in modern abattoirs that complete the processing of the meat over the three days of the Eid. Distribution of this sacrificial meat goes to those in need in some 30 countries.
The rites of the pilgrimage are now completed. Pilgrims come out of Ihram and wear their normal clothes, but remain at Mina for the Eid Al-Adha, the festival that signals the culmination of the Hajj. Over the next two days, they stone the three pillars in the Jamarat, before performing the Tawaf Al-Wida', the Farewell Circumambulation of the Ka'abah before their departure from the city.
While not required as part of the Hajj, most pilgrims visit the Prophet's Mosque in Madinah during their visit to the Kingdom.