The most important way of worship performed in this month is "hajj", one of the five pillars of Islam. The Muslims from every part of the world assemble in Arabia to perform this unique way of worship. Hajj is a worship, which requires at least five days to be performed in its proper way. There are detailed rules for different acts of hajj for which separate books are available, and the present article does not aim at explaining all these details. However, some basic information about its obligation is being given here:
1. Hajj is obligatory on every adult Muslim who can afford to go to Makkah during the hajj season, whether on foot or by any other carriage.
2. If a person can travel to Makkah to perform hajj, but he cannot travel to Madinah, hajj is obligatory on him also. He can perform hajj without visiting Madinah.
3. A Muslim woman cannot travel for hajj unless she is accompanied by a mahram (i.e. husband or relative of a prohibited degree like son, father, brother etc.) If she does not find any mahram to accompany her, hajj is not obligatory on her until she finds one. However, she must make a will that in case she dies before performing hajj, his heirs should arrange for her hajj-e-badal out of her left over property.
4. Hajj is obligated only once in one's life. After performing the obligatory hajj; one is not required to perform it again. However, he can perform the nafl (optional hajj as many times as he or she wishes.)