Based on the search results, it is not clear which Islamic holiday Muslims are celebrating today. However, there are two official Islamic holidays: Eid Al-Fitr and Eid Al-Adha. Eid Al-Fitr is celebrated at the end of the month of Ramadan, while Eid Al-Adha lands on the 10th day of Dhu al-Hijjah, the final month of the Islamic calendar. It is worth noting that Shia and Sunni Muslims do not celebrate the same holiday schedule, and that practices vary by nation. Additionally, Muslims use a lunar calendar, so the dates of Islamic holidays move 10-11 days earlier each year on the solar calendar, which means that the actual dates may vary between different sources.