Eid ul-Adha is another important festival in the Muslim calendar.
Its also known as the Festival of Sacrifice. It celebrates a story about a prophet called Ibrahim (Abraham).
Some Muslims may regard this as the most important festival as it remembers the prophet Ibrahim's willingness to sacrifice his son when ordered to by Allah. This shows Ibrahim's obedience to God.
Eid al-Adha takes place on the tenth day of the last month of the Muslim calendar.
The Muslim calendar is a lunar calendar — it follows the moon. The months are based on the moon’s phases. That means it’s 11 days shorter than the Gregorian calendar. That's the one you use at school that has 365 days.
So Eid al-Adha is celebrated on a different day every year. This year it begins on July 19th and ends on July 23rd.
Today, with social distancing many of these celebrations may not be possible. Some celebrations could be just with immediate family or might be online.