Photos: Reactions to Paris terror attack German President Joachim Gauck gives a speech in front of Berlin's Brandenburg Gate as political and religious leaders attend a Muslim rally to condemn the Paris terror attacks, promote tolerance and send a rebuke to a growing anti-Islamic movement on Tuesday, January 13. Hide Caption 1 of 40

Photos: Reactions to Paris terror attack A woman in Tel Aviv, Israel, holds a pencil Sunday, January 11, showing solidarity for the 12 people who were killed in a shooting last week at the Paris office of French satirical magazine Charlie Hebdo. Her cell phone shows four people who were killed in a Paris standoff several days after the Charlie Hebdo attack. Hide Caption 2 of 40

Photos: Reactions to Paris terror attack The Empire State Building in New York is lit in the colors of the French flag on January 11, paying tribute to those who lost their lives in the Charlie Hebdo terrorist attack. Hide Caption 3 of 40

Photos: Reactions to Paris terror attack A man holds up a pen, signifying freedom of expression, during a gathering Friday, January 9, at JFK Plaza in Philadelphia. Hide Caption 4 of 40

Photos: Reactions to Paris terror attack Lights on the Arc de Triomphe say "Paris est Charlie" (Paris is Charlie) on January 9. Hide Caption 5 of 40

Photos: Reactions to Paris terror attack Journalists and other people in Hong Kong hold up pens and hold signs that say "Je suis Charlie" (I am Charlie) during a vigil on January 9. Hide Caption 6 of 40

Photos: Reactions to Paris terror attack Workers install a giant banner on the Cannes Festival Palace in Cannes, France, on January 9. Hide Caption 7 of 40

Photos: Reactions to Paris terror attack People gather in front of the French Embassy in Mexico City on Thursday, January 8. Hide Caption 8 of 40

Photos: Reactions to Paris terror attack A crowd gathers in Sydney on January 8 to show their support for Charlie Hebdo. Hide Caption 9 of 40

Photos: Reactions to Paris terror attack In remembrance of the victims, the Eiffel Tower goes dark on January 8. Hide Caption 10 of 40

Photos: Reactions to Paris terror attack A man holds a pencil in front of Notre-Dame Cathedral during a moment of silence January 8 in the French capital. Hide Caption 11 of 40

Photos: Reactions to Paris terror attack Police observe a moment of silence January 8 in Rennes, France. Hide Caption 12 of 40

Photos: Reactions to Paris terror attack People in Istanbul pay tribute to the victims of the attack on January 8. Hide Caption 13 of 40

Photos: Reactions to Paris terror attack Journalists and supporters of press freedom hold placards saying "I am Charlie" outside the Foreign Correspondents' Club in Hong Kong on January 8. Hide Caption 14 of 40

Photos: Reactions to Paris terror attack Women hug each other during a solidarity rally outside the office of Charlie Hebdo on January 8. Hide Caption 15 of 40

Photos: Reactions to Paris terror attack A Romanian military member walks past a condolence book outside the French Embassy in Bucharest, Romania, on January 8. Hide Caption 16 of 40

Photos: Reactions to Paris terror attack People in Toulouse, France, observe a moment of silence in front of City Hall on January 8. Hide Caption 17 of 40

Photos: Reactions to Paris terror attack French journalists and their families show solidarity with the Paris victims outside the French Embassy in New Delhi on January 8. Hide Caption 18 of 40

Photos: Reactions to Paris terror attack Mourners hold signs depicting victims' eyes during a rally in New York on Wednesday, January 7. Hide Caption 19 of 40

Photos: Reactions to Paris terror attack People hold candles during a gathering at Place de la Republique, a square in Paris, on January 7. Hide Caption 20 of 40

Photos: Reactions to Paris terror attack People gather in Paris on January 7. Hide Caption 21 of 40

Photos: Reactions to Paris terror attack Flowers are placed at a candlelight vigil near the French Embassy in Tunis, Tunisia, on January 7. Hide Caption 22 of 40

Photos: Reactions to Paris terror attack People in Rio de Janeiro hold a sign that reads "We're all Charlie" on January 7. Hide Caption 23 of 40

Photos: Reactions to Paris terror attack Papers with "I am Charlie" written in various languages are left near candles at a vigil in front of the French Embassy in Berlin. Hide Caption 24 of 40

Photos: Reactions to Paris terror attack Employees put up a sign as a woman prepares to place a bouquet of flowers at the front gate of the French Embassy in Washington on January 7. Hide Caption 25 of 40

Photos: Reactions to Paris terror attack People in Brussels, Belgium, hold candles during a vigil on January 7. Hide Caption 26 of 40

Photos: Reactions to Paris terror attack People gather near candles in Lyon, France, on January 7. Hide Caption 27 of 40

Photos: Reactions to Paris terror attack People in Paris hold candles on January 7. Hide Caption 28 of 40

Photos: Reactions to Paris terror attack A man holds a candle and a sticker that translates to "I am Charlie" during a vigil in Paris on January 7. Hide Caption 29 of 40

Photos: Reactions to Paris terror attack People gather in London's Trafalgar Square on January 7. Hide Caption 30 of 40

Photos: Reactions to Paris terror attack People gather in front of city hall in Rennes on January 7. Hide Caption 31 of 40

Photos: Reactions to Paris terror attack A portrait of French cartoonist Georges Wolinski, another victim of the shooting, is seen in Marseille, France, on January 7. Hide Caption 32 of 40

Photos: Reactions to Paris terror attack People hold up pens as a show of support in Rennes on January 7. Hide Caption 33 of 40

Photos: Reactions to Paris terror attack People light candles during a vigil in Geneva, Switzerland, on January 7. Hide Caption 34 of 40

Photos: Reactions to Paris terror attack Journalists with Agence France-Presse hold signs reading "I am Charlie" as they observe a minute of silence on January 7. Hide Caption 35 of 40

Photos: Reactions to Paris terror attack A man in Paris raises a pen on January 7. Hide Caption 36 of 40

Photos: Reactions to Paris terror attack People gather at the Place Royale in Nantes, France, on January 7. Hide Caption 37 of 40

Photos: Reactions to Paris terror attack The French national flag flies at half-staff on the roof of the French Embassy in Berlin. Hide Caption 38 of 40

Photos: Reactions to Paris terror attack People light candles at the Place de la Republique on January 7. Hide Caption 39 of 40