Over a million Muslims have begun the once-in-a-lifetime pilgrimage, Hajj, on Wednesday in Saudi Arabia's Mecca, as additional measures are taken to contend with this year's sweltering heat, expected to exceed 40 degrees Celsius.
Over the span of five days, Muslim pilgrims - who can afford it and are physically fit - will immerse themselves in religious rituals that originated more than 1,400 years ago.
After entering Mecca, pilgrims will start their journey by circling the Kaaba, a black cube-shaped structure in the centre of the Great Mosque and Islam's holiest site, seven times in a anti-clockwise direction to express a unified devotion to one God.
Pilgrims will then travel to other sacred sites in Mecca, where they will perform additional rituals and acts of worship. Before leaving the holy city, Muslims will circle the Kaaba another seven times, signifying a spiritual farewell to the sacred sanctuary.
A successful completion of the Hajj, a spiritual experience of a lifetime, is a chance to seek God's forgiveness and can wipe the slate clean of past sins. While it's only required to do the pilgrimage once in a lifetime, some Muslims perform the Hajj multiple times.
Soaring summer temperatures
The Hajj occurs once a year during the 12th and last month of the Islamic calendar, called the lunar month of Dhul-Hijja. This year, the annual pilgrimage falls at the start of summer, making the heat an additional challenge to pilgrims completing the journey.
After last year's suffocating temperatures, reaching up to 47 degrees Celsius, resulted in more than 1,300 deaths, Saudi authorities are taking additional measures to ensure the safety of visitors.
This year, Riyadh has spent billions of dollars on crowd control and cooling systems. The world's largest and a one-of-a-kind cooling system installed in the Grand Mosque will keep pilgrims comfortable at temperatures ranging from 22-24 degrees Celsius, local media reported.
Pilgrims are also being told to avoid going out during the day and uncovering their heads, unless necessary such as during rituals and are given an official safety kit offering advice on what to wear and bring and explaining how to recognise and treat heat exhaustion and dehydration symptoms.
Representing one of the biggest policy changes in years, Riyadh has also introduced a ban on the participation of children younger than 12 years old in this year's Hajj.
Children are exempt from doing the Hajj and are not required to fulfil other religious obligations, such as praying and fasting, until they reach puberty.
Hajj is one of the Five Pillars of Islam, in addition to faith, prayer, almsgiving and fasting.
