Islamic New Year, December 18th, is a cultural celebration in which Muslims celebrate the month of Muharram which marks the beginning of the liturgical year.
Muharram is historically tied to the Islamic prophet Muhammad who emigrated from Medina to Mecca in 1662 A.D. Because of its historical roots, the Islamic New Year is celebrated differently. Some celebrate Muharram relatively quietly through prayer and reflection, while other Muslims celebrate Muharram by exchanging cards. As far as differences in celebration for Shia and Sunni Muslims, both groups see this particular holiday as a somber remembrance as it also encapsulates the Battle of Karbala and the death of Caliph Abu Bakr. However other than these differences, Muharram is remembered as a day of self-reflection as well as family gathering through special prayers and readings such as the hijra from the Koran. These special prayers and readings are what unite Muslims during this time of year and serve as a reminder of the prophet Mohammed’s daring emigration from
Sources:
http://www.newyearfestival.com/islamic-new-year.html
http://en.wikipedia.org/wiki/Islamic_New_Year
http://www.indobase.com/holidays/new-year/newyear-in-different-religions/islamic-new-year.html