Hajj is the grave of Propet Mohammed and every muslim must go there at least once in this lifetime. I've never been their yet but i intend to soon. Most of ma relatives have and they say it's the most beautiful and relaxedplace they have ever been to. They feel deperessed o the Hajj season is over, they say they would do anything to goo bak. =)
Muslims from all over the world from different races and cultures gather at the the Hajj. This gives a sense of community. The event of id-ul-adaha after the hajj is not only celebrated by the pilgrims but by the whole Muslim community.