Here’s what to know about Eid al-Fitr, Islam’s biggest holiday

More than one billion Muslims around the world will celebrate Eid al-Fitr this week, as the month-long Ramadan fast ends and the festivities begin. The celebrations mark a time when communities within the Muslim world come together.

What is Eid al-Fitr?

One of the most important days for Muslims, the holiday is the “festival of breaking the fast.”

Families and friends gather to show gratitude to Allah while celebrating the end of Ramadan, the four-week daytime fast that marks the month Muslims believe their Holy Book, the Quran, was revealed to the Prophet Mohammed. During this period, Muslims refrain from eating and drinking from sunrise to sunset. Ramadan is one of the five Pillars of Islam, requiring prayer five times a day and generally encouraging a more reflective behavior.

Eid al-Fitr doesn’t have any historical links; instead, the celebrations focus on the community and family, and a spirit of generosity is encouraged.

When is Eid al-Fitr?

The holiday is set by Islam’s lunar calendar and depends on the sighting of the new moon. Saudi Arabia’s Supreme Court announced this year’s Eid al-Fitr would begin on Monday, according to state-run Saudi News Agency. Some countries celebrate it a day later. Ramadan and Eid do not fall on the same date each year for the same reason. Time-zones also impact when Eid begins.

Once Eid starts, the celebrations can last for up to three days in most countries.

How is Eid celebrated?

During the day, Muslims gather in large open spaces or mosques for special prayers, called Salat al-Eid, which are usually followed by a small breakfast — their first daytime meal in a month.

Gifts are usually exchanged, and almsgiving is also a common practice. Another custom involves donning new clothes for the day, which marks a spiritual renewal.

Unsurprisingly, food is an important part of Eid al-Fitr, as feasting takes the place of fasting. After a month of the latter, delicacies and heavy foods will reign at the holiday’s lavish dinners.

CNN’s Matt Rehbein and Lyric Lewin contributed to this report.