Muslims around the world are celebrating Eid al-Adha, one of the two most important festivals in the Muslim calendar.
The five-day holiday, also known as the Feast of the Sacrifice, or Greater Eid, is distinct from Eid-al-Fitr, which marks the end of Ramadan.
Centred on prayer and animal sacrifice, Eid al-Adha symbolises Ibrahim's willingness to sacrifice his son as a sign of devotion to Allah.
How many Eids are there?
Two. Eid-al-Fitr, also known as Lesser Eid, marks the end of Ramadan, when Muslims break their month-long fast. The date of Eid-al-Fitr is determined by the confirmed sighting of the new moon. This year, the festival was celebrated on 25 June.
What does Eid al-Adha celebrate?
Islamic scripture tells how Allah commanded Ibrahim – known as Abraham to Christians and Jews – to sacrifice his son as a test of his devotion. Despite his love for the boy, Ibrahim duly prepared to carry out Allah's command. However, at the last moment, Allah tells Ibrahim to spare the child and sacrifice something else instead. In remembrance of Ibrahim's willingness to submit himself to the divine will, Muslim families traditionally sacrifice an animal during Eid al-Adha.
Non-Muslims will probably recognise the story from the Bible, where it appears in a similar form. Interestingly, Muslim scholars generally identify the son in question as Ishmael, Abraham’s son by his concubine Hagar, whereas in the Jewish and Christian tradition it is Isaac, Abraham's son with his wife Sarah, who narrowly avoids sacrifice.
Another difference is that, in the Islamic version of the tale, Ibrahim tells Ishmael about Allah's command, whereas the Biblical Abraham did not reveal his intentions to Isaac. As the Koran tells it, Ishmael readily accepts his fate and urges his father to comply with Allah's will. Therefore, Eid al-Adha is a commemoration of both father and son for their example of obedience and submission to the divine will.
When is Greater Eid this year?
The date of Eid al-Adha also varies in accordance with the Islamic lunar calendar, falling on the tenth day of Dhu al-Hijjah, the 12th month. The exact beginning of the festival varies depending on location, but in the UK, Eid al-Adha begins on Friday 1 September and ends on Tuesday 5 September.
How is Greater Eid celebrated?
In Muslim countries, Eid al-Adha is a public holiday that involves animal sacrifice, prayers and family gatherings. The day begins with morning prayers, followed by visits to family and friends and the exchange of food and gifts. Muslims traditionally greet each other on the day by wishing one another "Eid mubarak" (Blessed Eid) or one of many regional variations on the blessing.
Worshippers will slaughter an animal, typically a sheep or a goat, during Greater Eid celebrations as a symbol of Ibrahim's sacrifice to Allah. The animals have to meet certain standards in order to qualify for sacrifice, Arab News reports. They cannot be ill, blind, visibly lame and emaciated and minimum age restrictions apply. Believers are expected to share their food with the less fortunate, as well as make donations to charity to mark the festival.
In Pakistan alone, nearly ten million animals are slaughtered on Eid, the International Business Times reports. In Britain, anyone wishing to sacrifice a sheep has to make arrangements for it to be slaughtered humanely.
The eye-catching centrepiece of the festival, however, is the sight of around two million worshippers dressed in white gathering at Mecca for a five-day pilgrimage called Hajj.
What does the Hajj involve?
The Hajj is the pilgrimage to Mecca, Islam's holiest site, and is an integral part of the Muslim faith. According to the Koran, all Muslims who can afford to should make the journey to Saudi Arabia at least once in their lifetime. Every year, at least two million will make the pilgrimage, circle the huge black Kaaba shrine - built by Ibrahim, according to Islamic tradition - and pray to Allah. The prophet Muhammad said that a person who performs Hajj properly "will return as a newly born baby [free of all sins]".
Pilgrims usually fly to Jeddah and then travel by bus to Mecca, where there are two rituals to perform: the lesser pilgrimage, or Umrah, and the main pilgrimage, or Hajj. Pilgrims are expected to wear special white clothes - also called ihram - and to carry out several days of rituals where they pray, repent for past sins and take part in a symbolic "stoning of the devil".
The sheer number of believers able to carry out their religious duty thanks to modern transporation has made the 21st century Hajj a spectacular sight, but also a nightmare for Saudi authorities trying to keep upwards of two million pilgrims safe. In 2015, more than 2,000 people were crushed in a bottleneck of densely packed crowds, the deadliest incident in Hajj history. Since the tragedy, the Saudi government has deployed extra security forces and installed thousands of CCTV cameras to monitor the crowds.
Around the world some 1.5 billion Muslims are currently celebrating Islam's principal annual festival: Eid-ul-Adha, or the Festival of Sacrifice. The festival lasts for four days, during which time Muslims traditionally greet each other with the words "Eid Mubarak" or "Blessed holidays!"
United in prayer: the Festival of Sacrifice marks the highpoint of the Muslim hajj – the pilgrimage to Mecca. All Muslims are expected to make a pilgrimage to Mecca once in their lifetime, but not everyone can afford to. That′s why celebrations are held around the globe, such as here in Nairobi, and prayers are said everywhere
Animal sacrifices: every year, as here in India, millions of sheep, lambs, cattle and - in some regions - camels are slaughtered. This is in memory of the prophet Abraham (Ibrahim), who was prepared to sacrifice his son to God (Allah). But Allah was merciful – so the story goes – and Abraham was allowed to sacrifice a sheep instead
Holy ritual: the slaughter of cloven-hoofed animals is another aspect of the festival for which people gather together. In Egypt’s capital, Cairo, Muslims take part in the holy ritual. At the end the meat is distributed among the believers: a third is for the family, a third for friends and a third is given to the poor
A family affair: many Muslims are keen to get home for the beginning of the Festival of Sacrifice, known in Arabic as ″Eid-ul-Adha″. It′s traditionally a time for friends and family to get together. Thousands of people here are trying to catch the last train from the Bangladesh capital Dhaka. Some 90 percent of the population are Muslim
Filigree patterns: since the Festival of Sacrifice (Eid-ul-Adha) is a special occasion, many Muslims dress up. In Bangladesh, Pakistan and many other countries, the women apply henna tattoos to their hands. Believers put on their best clothes and most valuable jewellery to attend the prayers and celebrations
Roses for the dead: even those who have already passed on are remembered during Eid-ul-Adha. These Muslims in Hyderabad, India are packing roses into little bags. Later the roses will be placed on the graves of the dead as a sign of respect
Shrouded in smoke: this year believers in Indonesia have had to wear face masks in some areas. Smoke from illegal slash and burn operations in the rainforest on Sumatra have led to smog in many places. Indonesia has the largest Muslim population in the world
Under police protection: terrorist attacks have become the order of the day during Eid ul-Adha in recent years. Security is therefore high in many countries. Such as here in Karachi, Pakistan′s largest city, which has an estimated population of 15 million
Celebrating under fire...: Muslims in Syria are also celebrating Eid-ul-Adha. In the Syrian town of Idlib, some 60 kilometres southwest of Aleppo, these children are enjoying the holiday – despite the civil war and daily bombing raids run by the Syrian air force
...and in safety: this young refugee has been given a balloon to celebrate the festival. In many refugee shelters in Germany and Austria, Muslims have come together to cook, pray and celebrate Eid-ul-Adha – no longer in fear of their lives