Ramadan is a 30-day Islamic holiday that falls on the ninth month of the Islamic calendar.

Islam uses a lunar calendar that begins each month with the sighting of the new moon. Because the lunar calendar is 11 days shorter than the solar calendar, Ramadan "moves" each year.

This year, the first full day of Ramadan began Aug. 11 in North America.

For more than a billion Muslims around the world (including more than 8 million in North America), Ramadan is a month of blessing marked by prayer, fasting and charity.

Its themes focus on self-sacrifice and devotion to the Islamic deity known as Allah.

According to traditional Islamic teachings, Muslims believe that during the month of Ramadan, Allah revealed the first verses of the Quran, the holy book of Islam.

At many mosques during Ramadan, about one-thirtieth of the Quran is recited each night in prayers known as "tarawih."

In this way, by the end of the month, the complete scripture will have been recited. Muslims practice "Sawm" (fasting), for the duration of Ramadan.

They may eat or drink nothing, including water, until sunset. However, Ramadan observers may have "Suhoor," a meal eaten before the sun rises.

After sunset, a fast is broken with a meal known as "Iftar."

Fasting is considered one of the five pillars of Islam (profession of faith, prayers, giving of alms, fasting and pilgrimage to Mecca).

Practicing Muslims are tasked with completing all five pillars. According to Islam, fasting serves as a reminder of the suffering of the poor.

It is also an opportunity to practice self-control and to cleanse the body and mind.

During Ramadan, fasting is supposed to help Muslims feel spiritual devotion and kinship with fellow believers.

Ramadan ends with the festival of Eid al-Fitr, which will fall Sept. 10. Meaning "Festival of Breaking the Fast," Eid al-Fitr is one of the two major Islamic celebrations (the other occurs after the "Hajj," or pilgrimage to Mecca).

At Eid al-Fitr, observers adorn their homes with lights and decorations, give treats to children and visit with friends and family. Although charity and good deeds are in the teachings of Islam, they have a special significance at the end of Ramadan.

At the end of Ramadan, practicing Muslims are tasked with sharing their blessings by feeding the less fortunate and making contributions to mosques.