Eid al-Adha is celebrated on the 10th of Dhul Hijja , the 12th month of the Islamic lunar calendar, and again depends upon the crescent sighting for the first of the month. However, for those not performing Hajj, 'Eid al-Adha is the 10th of Dhul Hijja and one of the two most important celebrations of the year. In the Arabian Peninsula the calendar follows the local crescent sighting criterion, whereas in the U.S., the local crescent sighting is used for the determination of dates. Eid al-Adha may be celebrated for four days from the 10th to the 13th of Dhul Hijja . There are many other occasions which Muslims celebrate that are developments of local cultures and traditions.
Some celebrations are more widespread than the others.
These innovative celebrations are not found in the early generations of Muslims. This is the most common innovative celebration in the Muslim world. It is an innovation of later times, reported to have been introduced by the Fatimids in Egypt, a very corrupt Shi'ite sub-sect. In addition, authentic traditions add that he was led to the Heavens to visit the signs of Allah. Despite the lack of evidence, many Muslims continue to celebrate it.