Q&A: What is Ramadan and why do Muslims fast all day?

Millions of Muslims around the world on Monday marked the start of Ramadan, a month of intense prayer, dawn-to-dusk fasting and nightly feasts. Others will begin fasting a day later, Tuesday, due to a moon-sighting methodology that can lead to different countries declaring the start of Ramadan a day or two apart. 

Here are some questions and answers about Islam's holiest month:

Many Muslims to begin fasting for month of Ramadan on Monday

Millions of Muslims around the world will mark the start of the holy month of Ramadan on Monday, a time marked by intense prayer, dawn-to-dusk fasting and nightly feasts.

Saudi Arabia's state TV announced the new moon of Ramadan was spotted Sunday evening. Local media in Indonesia, the world's most populous Muslim country, also said Muslims there would begin fasting Monday, as will Muslims in Singapore, Yemen, Lebanon, Syria, Qatar, Kuwait, Jordan, Egypt, the United Arab Emirates, Afghanistan and the Palestinian territories, among others.

Muslims worldwide to mark the start of Ramadan on Thursday

Muslims around the world will mark the start of Ramadan on Thursday, a month of intense prayer, dawn-to-dusk fasting and nightly feasts.

Muslims follow a lunar calendar and a moon-sighting methodology that can lead to different countries declaring the start of Ramadan a day or two apart. However, this year religious authorities in Saudi Arabia, Egypt, Iran, Indonesia and most other parts of the world announced based on their sightings of the moon that daily fasting would begin Thursday.

Ramadan (Pakistan)

Pakistani girls show their hands painted with henna ahead of the Muslim holiday of Eid al-Fitr in Karachi, Pakistan, Monday, July 28, 2014. Pakistani Muslims will celebrate the Eid al-Fitr holiday that marks the end of the holy fasting month of Ramadan.  

Ramadan (Sri Lanka)

Sri Lankan Muslim girls pray as they celebrate Eid al-Fitr in Colombo, Sri Lanka, Tuesday, July 29, 2014. Millions of Muslims across the world are celebrating the Eid al-Fitr holiday, which marks the end of the month-long fast of Ramadan.  

Ramadan (India)

Indian Muslims offer Eid al-Fitr prayers near the Quli Qutub Shahi tombs in Hyderabad, India, Tuesday, July 29, 2014. Millions of Muslims across the world are celebrating the Eid al-Fitr holiday, which marks the end of the month-long fast of Ramadan.  

Ramadan

An Indian Muslim girl displays her henna decorated hands at a roadside stall ahead of the Muslim festivities of Eid al-Fitr, in Mumbai on July 28, 2014. Muslims around the world are preparing to celebrate the Eid al-Fitr holiday, which marks the end of the fasting month of Ramadan.

AP PHOTOS: As Ramadan fast ends, the feasts begin

This Sunday, July 6, 2014 photo, shows an Iraqi family waiting to break their fast during the hold month of Ramadan in Basra, Iraq. For the millions of Muslims abstaining from food and drink from sunrise to sunset every day during Islam’s holiest month of Ramadan, that first sip of water after a grueling fast is by far the most anticipated moment of the day.

Ramadan

Ramadan

Ramadan rush: Mega-rich shoppers descend on London

Before the fast, let there be a shopping feast.

From Harrods in Knightsbridge to the glittering diamond stores in Mayfair, London has long attracted big spenders. But every year around the holy month of Ramadan, which starts this weekend, a wave of spectacularly rich Middle Eastern shoppers arrives and takes retail therapy to a whole new level - complete with an entourage of bodyguards, chauffeurs, and Gulf-registered Rolls-Royces and Ferraris flown in just for the occasion.