Demonstrators in dozens of major cities carried "Je Suis Charlie" ("I am Charlie") signs and marched in the streets Sunday to show support for a massive rally in Paris. An estimated 3 million people came out in the French capital to protest last week's terrorist attacks on Charlie Hebdo, a satirical magazine, and to demonstrate their right to free speech.

As of 5:30 p.m. EST, protests in Paris were slowly winding down after people spent hours jammed into the city's main Republique and Nation squares. Sunday's rally was the biggest in French history and was attended by more than 50 world leaders.

Charlie Hebdo's editorial headquarters was attacked Wednesday by Islamist terrorists who were angered by the publication's depiction of the Prophet Muhammad. Twelve people were killed at the scene, and five other victims were killed in separate incidents on Thursday and Friday. The three-day terror spree prompted calls around the world for religious tolerance and freedom of expression.

"Our entire country will rise up toward something better," French President François Hollande said.

In Berlin, some 18,000 people gathered outside the French embassy wielding flowers and pencils to show solidarity with the Charlie Hebdo's illustrators, the Associated Press reported. Many at the protest were French citizens, but a mix of European languages could be heard buzzing throughout the crowd.

"It's important that we're all here. We are sending a clear signal that we won't let the terrorists win," Polina Panfilova, a Russian university student, told the AP. Her Dutch friend, Marieke Zwarter, said she attended the Berlin rally to "show that we should not be afraid and will not allow these terrorists to divide our societies."

Flags flew at half-staff over Austria's government buildings in Vienna where around 12,000 residents, religious leaders and officials gathered near the French embassy, the AP said. Some 20,000 people marched silently in Brussels, carrying signs that read "United Against Hatred." In London, city landmarks were bathed in red, white and blue lights, the colors of the French flag.

Other European demonstrations took place in Rome, Madrid, Stockholm, Moscow and Istanbul. Further east, hundreds of people rallied in Tokyo and Sydney, and in the Americas, protests were held in Rio de Janeiro, Buenos Aires and Havana. 

U.S. protesters gathered in Washington, New York, Denver and Boston. Thousands of Canadians rallied in Toronto, Ottawa, Montreal and Quebec City, singing the French national anthem and waving the flags of France and the province of Quebec.

Israelis marched through Jerusalem and expressed support for the French Jewish community, the AP reported. Demonstrators held "Israel Is Charlie" signs, and city leaders said they would set up a makeshift memorial for the 17 people killed in last week's Paris attacks.

Palestinians in Gaza City held a small candlelight vigil for the victims. In the West Bank, a couple of hundred people held a solidarity rally in the city of Ramallah. Yasser Abed Rabbo, a senior Palestinian official, told the AP France and the Palestinians share the same values of liberty, equality and "saving the modern civilization against the criminals who … have attacked the heart of France."