The twelfth and final month of the Islamic calendar is Dhu al-Hijjah. Dhu al-Hijjah is the month of the Hajj. The Hajj, often referred to as the pilgrimage to Mecca, is an obligation of every able-bodied Muslim who can afford to do so. The Hajj itself is more than a simple trip to Mecca to be made at the believer's leisure, it is a specific set of rituals and prayers and travels in the area of Mecca to be made from the 8th through 10th of Dhu al-Hijjah, including a visit to the Kaaba, the house of Allah. The four day festival of Eid ul-Adha, celebrated by Muslims worldwide regardless of their ability to participate in the Hajj that year, starts on the 10th of Dhu al-Hijjah. The duties of the pilgrim continue during Eid ul-Adha as well. As a lunar calendar based on visibility of the new moon, the Islamic calendar does not line up exactly with the Western calendar, but in 1427 AH / 2006-2007, Dhu al-Hijjah occurs from 21 December 2006 to 18 January 2007, with the Hajj starting on 28 December and Eid ul-Adha starting on 30 December. For future years, the following estimated dates apply:

Islamic Year	Western Year	First Day	Start of Hajj 8th Day	Eid ul-Adha 10th Day	Last Day
1428 AH	2007 – 2008	11 December 2007	18 December 2007	20 December 2007	9 January 2008
1429 AH	2008	30 November 2008	7 December 2008	9 December 2008	28 December 2008

The Hajj and the Kaaba predate Islam. According to Islamic history, the Prophet Ibrahim (known as Abraham to the Jews and Christians) built the Kaaba, the house of Allah, at His command for use in the Hajj. By the time of Muhammad, polytheistic and immortal practices had taken over and Muhammad restored the original worship practices. Non-Islamic history includes pre-Islamic references to the Kaaba and pilgrimages to it, but no references to an Abrahamic origin.

The Hajj itself consists of several stages, all associated with prayer and study. The first day consists Tawaf, circling the Kaaba seven times symbolizing Allah's place at the center of all human actions; performing Sa'ee between Safa and Marwah, commemorating Hagar's search for water for her and Ibrahim's son Ishmail; and an overnight trip to Mina, about three miles from Mecca. The second day is spent nine miles away in Arafah praying and studying Koran. After sunset, pilgrims head to Muzdalifah, a city half-way between Arafah and Mina, for more prayers and to collect pebbles for use in the next days. Before sunrise on the third day, Eid ul-Adha, pilgrims head for Mina. En route, they throw pebbles at a pillar, Jamrat al-Kubra. This is symbolic of stoning the devil. In Mina, pilgrims perform a sacrifice and often bathe, change and cut their hair to symbolize a fresh start due to the forgiveness of sins. Depending on personal circumstances and the type of pilgrimages chosen, the pilgrim can make a trip into Mecca to perform Tawaf and Sa'ee. On the fourth and fifth days, pilgrims stone the Jamrahs, three pillars symbolic of the devil's three appearances to Muhammad, with the pebbles they previously collected. It is optional to stone the Jamrahs for a third day as well. Pilgrims finish their hajj by returning to Mecca for a final Tawaf.

Eid ul-Adha, the festival of sacrifice, commemorates the willingness of the Prophet Ibrahim to follow God's command and sacrifice his son Ishmael. It is one of the major festials of the Islamic year. Pilgrims celebrate Eid ul-Adha simultaniously with the last three days of the Hajj, but Muslims worldwide celebrate as well. Muslims wear their best clothes and attend a special morning prayer service. Cards, gifts, visiting, and special meals are a common part of the celebrations. Those who can afford to do so sacrifice a domestic animal or otherwise share meat with friends, family, and the poor.

The Pilgrimage to Mecca: One Woman's Journey - a Saudi reporter's discussion of her experiences on pilgrimage, from The Christian Science Monitor