In 2005 and 2006 a Danish newspaper, followed by other European papers, published 12 cartoons depicting the prophet Muhammed – an act considered blasphemous by many Muslims. (Not all Muslims believe it's forbidden to depict the prophet. The New York Times notes evidence of a tradition of Islamic and Western art representing the prophet without negative repercussions).
The cartoons − many of which were unflattering − triggered violent protests throughout Muslim communities in Africa and the Middle East. Rioting lasted for close to a month, embassies and churches were burned, and rioters clashed with police. In the end, more than 200 people died and many more were injured.
Violence has flared up from time to time as the cartoons have been reprinted or referenced. In 2008, after the foiling of a murder plot against one of the Danish cartoonists, Kurt Westergaard, 17 Danish newspapers republished the incendiary cartoons in solidarity with Mr. Westergaard. This reignited protests across the Muslim world, not just in the Middle East, reaching as far as Indonesia.
After the cartoons were reprinted, the parliamentary speaker in Egypt claimed the cartoons violated the International Declaration of Human Rights, while Al Qaeda claimed responsibility for a revenge bombing outside the Danish embassy in Pakistan. In 2010 Pakistani officials briefly blocked Facebook after a proposed “Draw Muhammad Day” campaign was announced.