About 1 million Muslim pilgrims are visiting Mecca for the first Hajj since 2019, marking the largest Islamic pilgrimage since the COVID-19 pandemic upended the annual event. It is a scene that stirs hope — and relief — for Muslims around the world.

The Hajj pilgrimage is one of Islam’s five central pillars and a once-in-a-lifetime duty for all Muslims physically and financially able to make the journey, the Associated Press reported. It commemorates the story of Abraham who Muslims believe was commanded by God to build the Kaaba, the holiest shrine in Islam, as a metaphorical representation of his palace on earth. Pilgrims spend five days carrying out a set of rituals in the city of Mecca intended to bring them closer to God, including praying around the Kaaba. The black cube-shaped building lies at the center of Islam’s most important mosque, the Masjid al-Haram, and serves as a symbolic point of worship. Muslims around the world face in the direction of this building when performing their obligatory five daily prayers.

During the Hajj, pilgrims also visit key sites along a path traversed by the Prophet Muhammad some 1,400 years ago. The journey is meant to be a great equalizer and unifier among Muslims. Pilgrims wear simple clothing: For men, it’s typical to wear a white draping garment, while women wear conservative dress and headscarves, forgoing makeup, nail polish and perfume to draw closer to God.

The ritual was almost scrapped in its entirety in 2020, when as few as 1,000 residents of Saudi Arabia were permitted to take part. Some 60,000 residents attended last year. The unprecedented restrictions sent shockwaves through the Muslim world and devastated many believers, who often save up and wait for years to make the pilgrimage.

This year, the Hajj is open to just 1 million foreign and domestic pilgrims who have been fully vaccinated against the coronavirus, tested negative for COVID-19 and are between 18 and 65 years old, according to the AP. Authorities estimate 85% have arrived from abroad. With many more people applying to perform the Hajj each year than the kingdom can accommodate, the Saudi government controls the flow of visitors through annual quotas based on each nation’s Muslim population.

The Hajj lasts between five to six days and takes place every year during Dhu al-Hijja, the 12th and final month of the lunar-based Islamic calendar.