The annual haj pilgrimage, one of the Five Pillars of Islam, officially began on Monday.

More than 1.5 million pilgrims have arrived in Saudi Arabia from outside the country, Saleh bin Saad Al-Murabba, commander of the haj passport forces, said on Friday. The faithful have been pouring into the country for the haj against the backdrop of a tenuous ceasefire in the Iran war and related regional tensions and uncertainty.

Egyptian pilgrim Samya Abdul Moneim said she was grateful to God that she made it to the haj, which is required once in a lifetime of every Muslim who can afford it and physically able to make it.

“I am in a state of blessing and happiness,” she said in Mecca on Sunday. “It’s an indescribable feeling, truly. I mean, thank God, I am in a blessing.”

Typically on the first day, many pilgrims in Mecca converge on a vast tent camp in the nearby desert. Ahead of that, pilgrims have been circling the cube-shaped Kaaba in the Grand Mosque in sweltering temperatures. For pilgrims, haj can be a deeply moving spiritual experience and a chance to seek God’s forgiveness and the erasure of past sins. Pilgrims perform haj rituals over several days.

Some spend many years hoping and praying to one day perform the haj or saving up money and waiting for a permit to embark on the trip.