Also known as Eid-e-Milad, Milad un-Nabi celebrates the birthday of the Prophet Muhammad. The holiday also honours his life and teachings. Milad un-Nabi is observed on the 12th day of Rabi-ul Awwal, the third month of the Islamic calendar. While this day celebrates Muhammad's birthday, it is also a day of mourning. This is due to the fact that the Prophet Muhammad also passed away on the 12th day of Rabi-ulAwwal. Some people treat Milad un-Nabi as a festival holiday, but others regard it as solemn day.