When depictions of prophet Muhammad have outraged Muslims

A shooting at the Paris offices of Charlie Hebdo, a satirical French weekly, left 12 people dead Wednesday.

The perpetrators were allegedly responding to controversial cartoons the newspaper has published, sometimes showing the prophet Muhammad naked, other times showing him as sickly and in a wheelchair.

Here is a look back at other controversies that caused outrage in the Muslim world and steps that were taken to prevent any dangerous backlash.

Danish cartoons

In 2006, cartoons published in the Danish daily Jyllands-Posten, and re-printed in the Norwegian paper Magazinet, depicted Muhammad in an unflattering light, including one that showed him wearing a bomb in his turban. The cartoons sparked outrage among Muslims and resulted in protests throughout the Middle East, as well as threats of retaliation against those involved in the drawings. Saudi Arabia recalled its ambassador from Denmark, while Libya closed its embassy in Copenhagen.

Mozart Opera in Berlin pulled

After the Danish cartoon controversy, a leading Berlin opera house pulled Mozart's "Idomeneo" over fears that it could lead to dangerous reactions. In one scene, King Idomeneo "presents the severed heads not only of the Greek god of the sea, Poseidon, but also of Muhammad, Jesus and Buddha."

Swedish drawings

A year and a half after the outrage over the Danish cartoons, Swedish artist Lars Vilks displayed a rough sketch at a Stockholm seminar that showed Muhammad's head on a pig's body. The leader of al-Qaida in Iraq announced a reward for the killing of Vilks as well as another Swedish newspaper editor who published the cartoon.

The Met pulls three paintings

In a precautionary move, the Metropolitan Museum of Art pulled three early paintings of the prophet before the images were unveiled as part of its Islamic collection, according to the New York Post.

'South Park' censorship

"South Park," known for its brazen depictions of Jesus, Scientologists, Catholics and Jews, attempted to feature Muhammad in 2010. The show had done this two times before, but this attempt was stalled. After receiving threats from extremist groups, Comedy Central bleeped out all references to Muhammad, and all images of the prophet were censored.

Molly Norris and 'Everybody Draw Mohammed Day'

In 2010, Seattle-based cartoonist Molly Norris proposed that everybody create a drawing depicting Muhammad, as a response to death threats against those involved in the "South Park" segment that attempted to depict the prophet.

Norris drew a variety of objects, including a box of pasta and coffee cup, likening those to the prophet.

After her announcement of "Everybody Draw Mohammed Day," the then-leader of al-Qaeda in the Arabian Peninsula, Anwar al-Awlaki, said Norris has been put on an execution hit list.

'Innocence of Muslims'

A 14-minute, low-budget YouTube video released in 2012 led to protests across the Muslim world. This video depicted Muhammad as a womanizer, child molester, homosexual and a thug.

The demonstrations led to dozens of deaths and hundreds of injuries, and there are some reports that the clip provoked the 2012 terrorist attack in the Libyan city of Benghazi that left a U.S. ambassador dead.