The pilgrims will then spend the entire Friday at Arafat, continuing to pray while refraining from committing any sort of sins or engaging in material affairs.

Hundreds of thousands of Muslim pilgrims went out of Mecca on Thursday night to Mina Valley in Saudi Arabia for Islam's annual hajj pilgrimage.

In Mina, pilgrims prayed and had rest before moving on to Mount Arafat for the climax of the pilgrimage rituals on Friday.

The pilgrims will then spend the entire Friday at the holy site, continuing to pray while refraining from committing any sort of sins or engaging in material affairs.

Hajj is the fifth pillar of the Islamic faith and occurs in the 12th month of the Islamic lunar calendar, called Dhul-Hijjah, between the eighth and 13th days of the month.

On Saturday, which marks the Eid al-Adha feast, the pilgrims will begin performing another part of the Hajj rituals, referred to as Ramy al-Jamarat or stoning pillars symbolizing Satan in Mina. The stoning ritual denotes the rejection of sins and temptations.

Following the stoning ritual, the pilgrims will then shave their heads or cut a small portion of their hair for the symbolic renewal of their faith and sincere submission to God, the Creator.

The highly sacred religious ceremonies, highlighting the unity of God and total submission to His commandments and decrees, will continue until Monday.

Making the Hajj pilgrimage and performing all of its rituals is one of the central pillars of Islam.

The pilgrims who come to Mecca are supposed to perform the minor Hajj once they reach the holy city. They enter the state of Ihram before coming to Mecca, which means they are prohibited from a number of acts.

The first rite pilgrims have to carry out in Mecca is called Tawaf or circling around the Ka’aba in the Grand Mosque seven times counterclockwise.

For Hajj pilgrims, the Ka’aba, also known as the Sacred House, is the centerpiece of their journey. The pilgrims circle around it seven times and praise Allah. It is the place inside which Imam Ali Bin Abi Talib (as), Prophet Mohammad's cousin and son-in-law, was born.

The second rite of the Hajj pilgrimage is called Sa’y. In this stage, the pilgrims travel seven times between two hills called Safa and Marva. The small mountains have now become part of the Grand Mosque.

The ritual commemorates the attempt by Hajar, Prophet Abraham (PBUH)’s wife, to find water for her son, Prophet Ismael (pbuh).

Saudi authorities say close to 1.4 million believers have come from abroad to follow the 1,400-year-old tradition of Prophet Mohammad (peace be upon him), alongside pilgrims from Saudi Arabia.

The world's biggest annual religious pilgrimage comes as authorities in the kingdom strive to protect pilgrims from two deadly viruses, Ebola and the MERS corona viruses.