Hundreds of thousands of people have gathered in Paris today to show solidarity against terrorism as well as a message of tolerance and unity. French president Francois Hollande was joined by British Prime Minister David Cameron, German Chancellor Angela Merkel, Turkish Prime Minister Ahmet Davutoglu, Israel Prime Minister Benjamin Netanyahu, and Palestinian Authority President Mahmoud Abbas, among several other heads of state and foreign dignitaries. Social media has been a major driver of the public consumption of Wednesday's shooting in Paris, where three gunmen killed twelve people in an attack on the office of Charlie Hebdo, a satirical magazine. The alleged motive behind this attack was retaliation for the magazine's mocking of Islam.   

Ambassador to France Jane Hartley represented the United States at the rally.   

British Prime Minister David Cameron recorded this video: