Tuesday marked the first day of the ninth month of the Islamic calendar, Ramadan, the holy month for Muslims.

Adults fast from sunset to sunrise and abstain from smoking and sex. The breaking of the fast at dusk is known as Iftaar and begins by eating dates. However, the practice may vary slightly among Muslims from different regions. The exceptions are for pregnant women, those who are ill or travelling, and for the physically weak.

The observation of Ramadan month marks the anniversary of the Koran being revealed to the Prophet Mohammed. It is observed annually after the sighting of the new moon and lasts for 29 or 30 days until the next new moon appears. The observance is regarded as one of the five pillars of Islam along with belief, worship, charitable donation and the pilgrimage to Mecca.

The Muslim holy book explains: "The month of Ramadan in which was revealed the Koran, a guidance for mankind and clear proofs for the guidance and the criterion [between right and wrong]."

Ramadan concludes with Eid ul-Fitr, when morning prayers are followed by feasting and celebrations.

Ramadan 2013 First Day of Holy Month for Muslims
A child copies worshippers at midday prayers at Strasbourg Grand Mosque Reuters
Ramadan 2013 First Day of Holy Month for Muslims
Learning young Reuters
Ramadan 2013 First Day of Holy Month for Muslims
A boy chooses prayer beads ahead of the holy month of Ramadan in Lahore Reuters
Ramadan 2013 First Day of Holy Month for Muslims
A worker cleans a chandelier inside the Badshahi mosque in Lahore. Reuters
Ramadan 2013 First Day of Holy Month for Muslims
A vendor displays traditional Muslim prayer caps Reuters
Malaysian Resort Owner Detained for Allowing Buddhist worship in Muslim Prayer Room, Resort may be Demolished
Malaysian Resort Owner Detained for Allowing Buddhist worship in Muslim Prayer Room, Resort may be Demolished Reuters
Ramadan 2013 First Day of Holy Month for Muslims
The Jakarta women at prayer Reuters
Ramadan 2013 First Day of Holy Month for Muslims
A Palestinian woman examines decorations for sale a day before the holy month at a market in the West Bank city of Nablus Reuters