Millions of Muslims around the world will mark the start of Ramadan on Wednesday in Turkey and Thursday according to the Saudi calendar, a month of intense prayer, dawn-to-dusk fasting and nightly feasts. Hilal (the crescent) coincides with the astronomical new moon. Since the new moon marks the beginning of the new month, Muslims can usually safely estimate the beginning of Ramadan, but georgraphical differences can change when Ramadan begins.
U.S. President Donald Trump released an official statement from the White House marking the holiday, "As so many people unite to celebrate Ramadan, Melania and I join in the hope for a blessed month. Ramadan Mubarak." The statement, however, did not appear on either Trump's or the White House's official Twitter accounts - a rare move for the avid social media friendly White House.
Here's a look at some questions and answers about Islam's holiest month:
WHY DO MUSLIMS FAST?
The fast is intended to bring the faithful closer to God and to remind them of the suffering of those less fortunate. Muslims often donate to charities during the month and feed the hungry.
Fasting is an exercise in self-restraint. It's seen as a way to physically and spiritually detoxify by kicking impulses like morning coffee, smoking and midday snacking.
Ramadan is a time to detach from worldly pleasures and focus on one's prayers. Many Muslims dress more conservatively during Ramadan and spend more time at the mosque than at any other time of the year.
Fasting during Ramadan is one of the five pillars of Islam, along with the Muslim declaration of faith, daily prayer, charity, and performing the hajj pilgrimage in Mecca.
HOW DO MUSLIMS FAST?
Observant Muslims abstain from eating and drinking from dawn to dusk for the entire month of Ramadan, with a single sip of water or a puff of a cigarette considered enough to invalidate the fast.
Muslim scholars say it's not enough to just avoid food and drinks during the day, though. Spouses must abstain from sexual intercourse during the day, and Muslims should not engage in road rage, cursing, fighting or gossiping.
Muslims are also encouraged to observe the five daily prayers on time and to use their downtime just before breaking their fast at sunset to recite Quran and intensify remembrance of God.
To prepare for the fast, Muslims eat what is commonly called "suhoor," a pre-dawn meal of power foods to get them through the day.
HOW DO MUSLIMS BREAK THEIR FAST?
Muslims traditionally break their fast like the Prophet Mohammed did some 1,400 years ago, with a sip of water and some dates at sunset. That first sip of water is by far the most anticipated moment of the day.
After a sunset prayer, a large feast known as "iftar" is shared with family and friends. Iftar is a social event as much as it is a gastronomical adventure. Across the Arab world, juices made from apricots are a staple at Ramadan iftars. In South Asia and Turkey, yogurt-based drinks are popular.
Across the Muslim world, mosques and aid organizations set up tents and tables for the public to eat free iftar meals every night of Ramadan.
CAN MUSLIMS BE EXEMPTED FROM FASTING?
Yes. There are exceptions for children, the elderly, the sick, women who are pregnant or menstruating and people traveling, which could include athletes during tournaments.
Many Muslims, particularly those who live in the U.S. and Europe, are accepting and welcoming of others around them who are not observing Ramadan. They also are not expecting shorter work hours, as is the case in the public sector across much of the Arab world during Ramadan.
However, non-Muslims or adult Muslims who eat in public during the day can be fined or even jailed in some Middle Eastern countries, such as Saudi Arabia and the United Arab Emirates, home to large Western expat populations in Dubai and Abu Dhabi.
Meanwhile, minority Chinese Uighur Muslims complain of heavy restrictions by the Communist Party, such as bans on fasting by party members, civil servants, teachers and students during Ramadan, as well as generally enforced bans on children attending mosques, women wearing veils and young men growing beards.
WHAT ARE SOME RAMADAN TRADITIONS?
Typically, the start of the month is welcomed with greetings such as "Ramadan mubarak!" Another hallmark of Ramadan is nightly prayer at the mosque among Sunni Muslims called "taraweeh."
In Egypt, a common sight during Ramadan is a lantern called the "fanoos," which is often the centerpiece at an iftar table and can be seen hanging in window shops and balconies.
In the Arabian Gulf countries, wealthy sheikhs hold "majlises" where they open their doors for people to pass by all hours of the night for food, tea, coffee and conversation.
Increasingly common are Ramadan tents in five-star hotels that offer lavish and pricey meals from sunset to sunrise. While Ramadan is a boon for retailers in the Middle East and South Asia, critics say the holy month is increasingly becoming commercialized.
Scholars are also disturbed by the proliferation of evening television shows during Ramadan. In Pakistan, live game shows give away gifts promoting their sponsors. In the Arab world, monthlong soap operas starring Egypt's top actors rake in millions of dollars in advertising.
HOW DO MUSLIMS MARK THE END OF RAMADAN?
The end of Ramadan is marked by intense worship as Muslims seek to have their prayers answered during "Laylat al-Qadr" or "the Night of Destiny." It is on this night, which falls during the last 10 nights of Ramadan, that Muslims believe that God sent the Angel Gabriel to the Prophet Mohammed and revealed the first versus of the Quran.
Some devout Muslims go into reclusion those final days, spending all of their time in the mosque.
The end of Ramadan is celebrated by a three-day holiday called Eid al-Fitr. Children often receive new clothes, gifts and cash.
Muslims attend early morning Eid prayers the day after Ramadan. Families usually spend the day at parks and eating — now during the day.