It was the biggest of its kind in history.
Hundreds of thousands of people in cities around the world marched to bring attention to the issue of climate change on Sunday.
In New York, some 310,000 people walked through the streets of Manhattan holding signs and chanting slogans... (together united...)
In London, celebrities like actress Emma Thomson and musician Peter Gabriel joined the march.
Gabriel said climate change is a real problem and can't be ignored any longer.
(SOUNDBITE) (English) PETER GABRIEL, MUSICIAN, SAYING:
"I am now certain that this is a very real threat to our own survival and that we are blindly ignoring it at our peril."
From Melbourne to Paris, in more than 160 cities protesters said their aim is a world run entirely on clean energy.
Some 120 leaders plan to meet Tuesday at the United Nations in New York for a summit on climate change.
It includes talks on ways to lower greenhouse gas emissions in 200 countri
