This week Sunni and Shia Muslims ushered in the Islamic New Year and the beginning of the holy month of Muharram. For Shias, the month also is a time to mourn the events that sparked the centuries-old schism between Shia and Sunni Muslims.1 Pew Research Center polls conducted in 2011-2012 find high levels of concern about sectarian tensions in several countries where Sunnis and Shias live side by side.