A man reads from the Koran, Islam's holiest book, during the holy Muslim fasting month of RamadanMOHAMMED ABED/AFP/Getty Images

The holy month of Ramadan, where Muslims from across the world observe fast from sunrise to sunset, will begin on May 15 and end on June 14.

But, what is Ramadan and why do people fast?

In the Islamic month of fasting, Muslims around the world are mainly committed to pleasing Allah.

The sighting of the crescent moon marks the beginning of the new month, and depending on the geographical location the dates may vary.

It is considered the most sacred month of the year for Muslims as Prophet Mohammed, according to Vox, said: "When the month of Ramadan starts, the gates of heaven are opened and the gates of hell are closed and the devils are chained."

During Ramadan, Muslims refrain from eating anything from dawn till dusk. They don't even drink any liquids, smoke cigarettes or engage in any sexual activity during that time. Chewing gum is also prohibited.

Elderly people and children are exempted from the fast. Pregnant women are also not expected to observe the fast.

It is the time when Muslims are urged to observe spiritual discipline — of deep contemplation of one's relationship with God. People also believe it is the time when people build self-control. They often indulge in extra prayer, increased charity and generosity, and intense study of the Quran.

The month-long fasting ends with a grand celebration called Eid al-Fitr. People come together to celebrate with near and dear ones. They exchange gifts, blessing and good wishes and enjoy a grand meal.