The violence, fueled mostly by religious zealots, reflects the tension between Muslims and the secular West that followed the wars in Afghanistan and Iraq.
Here are some of the most serious incidents:
MUHAMMAD CARTOONS
The September 2005 publication by the Danish newspaper Jyllands-Posten of cartoons depicting the Prophet Muhammad unleashed a wave of violent protests by Muslims, who believe any image of their religion's founder is forbidden. Dozens of people were killed in weeks of protests that included violent attacks against Danish missions in Syria, Iran, Afghanistan and Lebanon. At least six people were killed in a June 2008 suicide bombing at the Danish embassy in the Pakistani capital, Islamabad. Al-Qaida claimed responsibility, citing anger over the cartoons. The Danish government described the Muslim backlash as the country's worst international crisis since World War II.
SATANIC VERSES
British author Salman Rushdie's 1988 novel, "Satanic Verses," inspired in part by the life of Muhammad, won kudos from critics in Britain but prompted outrage among many Muslims, who considered it slanderous. Deadly riots against the book erupted in Islamabad, Pakistan and Mumbai, India, and the book was banned in South Africa, India, Pakistan, Bangladesh and several other countries. Iran's Ayatollah Ruhollah Khomeini issued a religious edict in 1989 calling for Rushdie's death, leading the writer to live in hiding for a decade. Although Rushdie was never physically harmed, his Japanese translator was stabbed to death in 1991 and his Italian translator was injured in a stabbing that same year
VAN GOGH ASSASSINATION
Dutch filmmaker Theo van Gogh, an outspoken critic of Islam whose film "Submission" criticized the treatment of Muslim women, was shot dead in November 2004 as he bicycled in the capital of the Netherlands, Amsterdam. A 26-year-old Dutch citizen of Moroccan origin, Mohammed Bouyeri, was convicted of the murder and sentenced to life imprisonment. Van Gogh's assassination set off a wave of more than 170 small reprisal attacks against mosques and churches over the following weeks, according to a report by the Anne Frank Foundation and the University of Leiden.
"BURN A QURAN DAY"
A 2010 call by Florida preacher Terry Jones to burn Qurans on the ninth anniversary of 9/11 alarmed the U.S. military, which feared the move would endanger the lives of American troops fighting Islamist extremists in Afghanistan and Iraq. Although Jones called off the burning, thousands of Afghans encouraged by the Taliban set fire to tires in the streets of the Afghan capital, Kabul, and other cities and chanted "Death to America." Police in a province near Kabul fired shots in the air to disperse a crowd trying to storm the governor's residence.
Jones' congregation went ahead with a Quran burning in March 2011, triggering protests across Afghanistan after video of the ceremony was posted on the Internet. In the most violent protest, hundreds of protesters stormed a U.N. compound in Mazar-i-Sharif in northern Afghanistan, killing seven foreigners, including four Nepalese guards.
MORE QURAN BURNING
In February, U.S. soldiers at Bagram prison in Afghanistan burned 315 copies of the Qurans and other religious materials that had been taken from Bagram's facility library for disposal. Word of the burning, which the U.S. said was unintentional, triggered scores of anti-American protests across the country which left more than 30 Afghans and six U.S. soldiers dead. They included two U.S. troops who were shot by an Afghan soldier and two U.S. military advisers who were gunned down at their desks at the Afghan Interior Ministry. Six U.S. Army soldiers received unspecified administrative punishment for the burning, the Pentagon announced last month.