Transcript for Paris Unites in Solidarity Against Terrorist Attacks
of Isis is Al Qaeda. Tom? In Paris, the massive rally against terrorism that you see behind me. People as far as the eye can see taking to the streets of the wounded city. ABC news foreign correspondent terry Moran is there. Reporter: Today, it seemed, freedom itself was on the March in Paris. 1.3 million in the streets. A March on a scale not seen since the liberation of Paris in world war ii. And as we met people in the vast crowd, the told us, the declared to us, the same thing. We are not afraid, we are not afraid. Reporter: Security was very tight, thousands of troops and police on the streets. Paris still jittery after a week of terror. But they still came. ABC's Matt Guttman joined the marchers. We've been here for five hours and we've seen this ceaseless river of humanity surround us. Old, young, from all nationalities here, all races and creeds here. Reporter: Around the world so many more marching in solidarity with the French. Berlin, Moscow, Cairo, Jerusalem, Washington, D.C., Tokyo. And everywhere, that sign. Je suis Charlie. I am Charlie. In the tribute to the fiercely satiric magazine where the rampage began. Chole verlhac, widow of the magazine's famous cartoonist tignous, who now must raise their four children, the youngest 5 years old, alone, told us. I always supported him in all that he did. And I am so proud. So proud. Reporter: An emotional, even triumphant day. But urnlgtd beneath it all is anxiety. Fear of copy cat attacks. Last night, in Germany, a paper that had reprinted some cartoons was firebombed. There is a feeling here this isn't over. Tom?
This transcript has been automatically generated and may not be 100% accurate.