Ramzan, the holiest month of the Muslim calendar, starts today. This is the month Muslims believe that the Quran, the holy book of Islam, was revealed to the Prophet Mohammad over 1400 years ago. 

Source: b'Muslims outside Jama Masjit in Delhi | Source: Reuters'

Because Muslims follow the lunar calendar, and moon sighting determines the start and end of the month, the date may vary from region to region. It ends with the three-day festival of Eid-ul-Fitr.

Here are some of the most beautiful pictures from around the world, of people observing the first day of Ramzan this year.

A street vendor sells the traditional licorice root drink 

Date sellers organise their wares before the day's fast ends

Children playing with traditional Arabic lamps called 'fanous'

A huge lantern is hung outside of Mohammad Al-Amin Mosque

A man decorates his shop with lights

Women walk in traditional Egyptian garb in el-Mezz road prior to evening celebrations

Dutch Muslims perform 'Tarawih', the evening prayer, at Mevlana Mosque

Palestinian children celebrate the beginning of Ramadan in conflict-torn Gaza

Muslims gather to catch the first glimpse of the crescent moon