More than 40 leaders from all over the world marched arm-in-arm through the streets of Paris on Sunday, joining more than a million demonstrators in a display of unity and solidarity after the city was rocked by three days of terrorist attacks that killed 17 people.
Family members of some of the victims joined the leaders in the front of the march, as did surviving members of the Charlie Hebdo newspaper, which was targeted by the Islamist terrorists.
Those marching included British Prime Minister David Cameron, German Chancellor Angela Merkel, Israeli Prime Minister Benjamin Netanyahu, and Palestinian President Mahmoud Abbas.
"Today, Paris is the capital of the world," French President Francois Hollande said. "Our entire country will rise up toward something better."
Millions of other people protested across France, and demonstrations were also held in cities around the world.
The French Interior Ministry said the scale of the march was "unprecedented." It said 3.7 million people marched across France, with between 1.2 and 1.6 million people flooding the streets of Paris. French news media estimated that the Paris figure could be as high as 3 million, well above the number of people who poured into the streets following the liberation of the city during World War II.
Protesters in Paris also sang John Lennon's song "Imagine."
Le Monde filmed this time-lapse video of the Paris march.
One of the surviving Charlie Hebdo staffers, Renald Luzier, or "Luz," was pictured at the march raising his fist in a defiant gesture.
Hundreds of thousands of protesters remained on the streets as night fell in the French capital.
Demonstrations have also been held around the world. In London, the facade of the National Gallery was illuminated in the colors of the French flag during a gathering for the victims.
Tower Bridge was also lit up in the colors of the Tricolore.
Demonstrators also marched in Brussels, Belgium.
And outside the Leaning Tower of Pisa in Italy.
In Buenos Aires, Argentina, a group of demonstrators marched behind a French flag and a sign reading "All United."
While in Madrid, members of Spain's Islamic community held a sign saying "Islam = Peace".
In Valletta, Malta, a protester held a sign reading "We are also Charlie."
While Israelis gathered in Tel Aviv to pay tribute to the victims of the attack on the kosher supermarket.
Nadhrat Mhadjoui, 42, told BuzzFeed News why she is marching:
I came here to say no to all the massacres happening around the world. It's happening to us in France. We're trying to do something about it. It didn't used to be like this. We lived in peace, there were no problems, and now we're in an unlivable situation.
President Hollande and Israeli Prime Minister Benjamin Netanyahu have arrived at Paris' Grande Synagogue to pay their respects to the Jewish victims of the attacks.
BuzzFeed News Reporter Rosie Gray spoke to 28-year-old Muslim Mohammad Habib, who was among the Paris marchers. He said:
I'm here because I feel shocked. I feel really shocked at what's happening in the world, not just what's happening in Paris the last few days.
We're here to say no to terrorism, we're here to say no to what's happening in the world, we're here to speak about the soldiers in Cameroon, that fight against Boko Haram, we're here to say no to the terrorists ruining the Nigerian country, we're here to say no to terrorism across the world.
Of course Charlie had the right in a free country to do what they wanted with the caricatures. But they should have also been conscious that they had shocked part of the Muslim community. It's not because we're in a free country that we should forget the values of living together. We have to be concerned with the people with whom we live. But I'm absolutely against this barbarism. That's not how we should show our disagreement with what Charlie Hebdo did.
Le Monde released this aerial footage of the march showing the large crowd numbers.
U.S. Attorney General Eric Holder said Sunday that the U.S. has “no credible information” about which extremist group sponsored the terror attacks in Paris that killed 17 people over three days.
Government officials confirmed to BuzzFeed News that Holder did not march in the Paris rally because he had to fly back to Washington for meetings. The U.S. was represented at the demonstration by its ambassador to France, Jane Hartley.
Protests were also held across France on Sunday, with police reportedly estimating that 300,000 people marched in Lyon. That's a quarter of the city's entire population.
Imam Abdel Ali Mamoun spoke to reporters at the march:
We didn't agree with Charlie. But Charlie had the right to say what he wants. [The terrorists] did not avenge the prophet. They insulted him. They tainted him with the blood of innocents.
BuzzFeed News reporter Anaïs Bordages took these pictures among the crowd at Place de la République.
"I am a cop," this woman's sign reads.
"Not in my name. Islam = love/peace/tolerance. Stop terrorism and Islamophobia."
Here are our stories on the victims of the attacks on the kosher supermarket and the Charlie Hebdo offices.
The French Ministry of the Interior said the march is "unprecedented" and that it is impossible to provide an exact figure on the number of demonstrators, according to multiple French news outlets.
Demonstrators held up signs depicting the eyes of slain Charlie Hebdo editor Stephane "Charb" Charbonnier.
These official information signs from Paris City Hall were broadcasting patriotic messages across the city.
It reads: "I am a police officer. I am Jewish. I am Muslim. I am Christian. I am an atheist. I am French. I am a citizen of the world. I am Charlie."
Here are more images of President Hollande marching alongside the other world leaders.
Israeli Prime Minister Benjamin Netanyahu is pictured waving, alongside Mali's President Ibrahim Boubacar Keita and European Commission President Jean-Claude Juncker.
President Hollande marched next to German Chancellor Angela Merkel, European Council President Donald Tusk, Palestinian President Mahmoud Abbas, and the King and Queen of Jordan.
Former French President Nicolas Sarkozy was also marching, as was Italian President Matteo Renzi, pictured right.
One man had fashioned a "weapon" out of pens to remember the Charlie Hebdo cartoonists and writers killed.
Here is an aerial shot of the Place de la République.
Surviving journalists from Charlie Hebdo led the march.
Charlie Hebdo contributor Patrick Pelloux was embraced by President Hollande.
Here is video of the moment the pair embraced.
Crowds could be heard chanting "Charlie!"
President Hollande marched arm-in-arm with other world leaders, including Germany's Angela Merkel, Israel's Benjamin Netanyahu, and the leader of the Palestinian Authority, Mahmoud Abbas.
This is a scene from a Paris street where the march was not scheduled to take place.
The Associated Press has filmed these scenes from the march.
Here is a map showing the route of the march.
More than 1 million people were expected to turn out for Sunday's demonstration to remember those killed in the attacks. Here, a massive crowd can be seen gathering in the République square before the scheduled march.
Thousands of extra police are on duty to ensure security for the march.
This is a breaking news story. Please check back here or at BuzzFeed News on Twitter for updates.