Ramadan 2017
Muslims will mark Ramadan with prayer and fasting Reuters

Islam is the second-largest religion in the world with roughly 1.6 billion followers around the world –nearly a quarter of the global population. Annually, more than a million people make the pilgrimage to Saudi Arabia for Hajj and Ramadan, two of the most important periods in the Islamic calendar.

Ramadan is one of the Five Pillars of Islam, and it occurs in the ninth month of the Islamic calendar. It is a period of fasting, prayer and charitable giving believed to mark the first revelation of the Quran to Islamic prophet Muhammad. This year, Ramadan begins on 26 May.

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According to Islamic belief, the Quran was revealed to Muhammad in 610 AD on Laylat al-Qadr, often translated as 'the Night of Power', one of the odd-numbered nights during the last 10 days of Ramadan.

Observance of Ramadan is stated in the Quran, Surah 2, Ayah 185.

"The month of Ramadan [is that] in which was revealed the Qur'an, guidance for the people and clear proof of guidance and criterion. So whoever sights [the new moon of] the month, let him fast it; and whoever is ill or on a journey – then an equal number of other days.

"Allah intends for you to ease and does not intend for you hardship and [wants] for you to complete the period and to glorify Allah for that [to] which He has guided you; and perhaps you will be grateful."

When is Eid al-Fitr and what is it?

Ramadan ends with the festival of Eid al-Fitr, which marks the first day of the Islamic month of Shawwal. Prayers are performed at mosques and families get together to break the fasting period. Eid al-Fitr is also a time of giving thanks to Allah for the strength to complete the fasting.

What are the Five Pillars of Islam?

Fasting during Ramadan is one of the Five Pillars of Islam – a series of five obligations that Muslims must carry out in order to live a responsible and proper life. Fasting is intended to help teach Muslims self-discipline and self-restraint.

Shahadah: A creed that declares belief in the 'oneness' of God and the acceptance of Muhammad as the prophet

Salat: Performing ritual prayers in the proper way five times each day

Zakat: Donating to charity to benefit the poor and needy

Sawm: Fasting during the month of Ramadan

Hajj: Pilgrimage to Mecca