Every year, scores of devout Muslims from around the globe make the trip to Mecca, Saudi Arabia, to perform one of the five pillars of Islam - Hajj.
The annual pilgrimage to Islam's holiest site is performed between the 8th and 12th of Dhu al-Hijjah – the last month of the Islamic lunar calendar – and coincides with the second and holiest Muslim holiday known as Eid al-Adha.
Home to the world's biggest Muslim population, Asia contributes to the majority – almost half – of all Hajj pilgrims where Saudi authorities assign a quota, approximately a place for each 1000 Muslims per country.
This year, 2 million people are expected to head for Hajj and 1,735,391 have arrived in the country already, according to the Saudi Press Agency.
But what does Hajj constitute and why is it so important to Muslims? Here's a look at what the journey means and entails from start to finish.
Why is it important?
Every Muslim who is physically and financially able, is required to perform Hajj at least once in their lifetime, as it is the 5th pillar of Islam – others being Shahadah (the declaration that there is one God and that Mohammad is his last prophet), Salat (daily prayers), Sawm (fasting during the month of Ramadan) and Zakat (charity).
What is it about?
Performing Hajj is supposed to signify one's commitment to God. During Ihram – a sacred state of abstinence prior to performing Hajj rituals – male pilgrims are required to dress only in two unstitched plain white cloths to symbolize equality in front of God where wealth, color and ethnicity don't matter.
What are the rites?
Over five or six days, pilgrims follow several rituals in which they emulate prophet Mohammad, who was the first person to perform the Hajj.
The rites include circling the Ka'abah seven times on the first and last day, and "Stoning of the Devil" – throwing pebbles at pillars representing satan.
What do they signify?
The rites largely honor the story of Abraham who was ordered by God to leave his wife Hagar and son Ishmael in the desert where they struggled to find water until the ZamZam well miraculously appeared. Abraham was then ordered to build the Ka'abah on the site, and later on Mohammad instructed the rites of Hajj.
The Day of Arafah
The climax of Hajj, however, is when pilgrims climb Mount Arafat which lies 20 km east of Mecca and spend the afternoon on the mountain praying and repenting to emerge clean of their sins. The Day of Arafah is the one preceding the first day of Eid al-Adha which lasts a total of four days.
After Arafah, pilgrims are required to slaughter an animal – usually a sheep – or ask someone to do it on their behalf. This is to commemorate prophet Abraham's narrative when he was asked by God to sacrifice his son (believed by Muslims to be Ishmael) as a test of his devotion, but the later was then replaced by a sheep.
While pilgrims are performing their Hajj rituals, other Muslims around the world celebrate Eid al-Adha (known as Sacrifice Feast) which falls on the 1st of September this year. Celebrations constitute of praying and sacrificing an animal to distribute its meat to the poor and needy, which results in surge in demand and cost of livestock.
The cost of Hajj
Depending on where pilgrims are arriving from – and the services they require – Hajj could cost anywhere from a few thousands to tens of thousands of dollars per person. The trip is usually organized by specialized tour operators and cover their transportation, accommodation as well as daily expenses.
Among those who performed Hajj are famous figures from around the globe.
These include Manchester United footballer Paul Pogba, former boxing champion Mike Tyson, Bollywood star Aamir Khan, late boxer and activist Mohammad Ali and American human rights activist Malcom X.