They called it “Earth Hour”. “An hour for the planet”. While inside the struggle to reach agreement went on, outside they gathered for a symbolic gesture.
To switch off the lights in Copenhagen and plunge the city into darkness for sixty minutes.
For those who turned out, it was another reminder of the need to act to tackle climate change.
“It is a statement. We want to tell the politicians, everyone, it’s now or never, you have to do something about it right now,“said one activist.
They marched in their hundreds to the City Hall, heeding the call from campaign groups WWF and Earth Hour Hopenhagen.
A rather more festive spirit compared to the violent scenes earlier in the day. But with the same message for the summit: save the planet.