It's finally happening, COP21 aka the most important meeting ever, is finally underway.
Leaders from around the world have reached Paris and will have a chance to come together, cooperate and put together a plan that seriously combats the worst effects of climate change.
You might have switched on your TV screens this week and seen the news presenter say something about COP21, that’s because hundreds of thousands of people from around the world have shown leaders and the media, that the climate isn't an issue they can continue to ignore anymore.
What
gets decided in Paris will have consequences for our oceans, forests and the arctic;
the consequences will be felt by every species and people the world over.
This isn't the first time leaders have had the chance to take bold action for
the people and the planet. For many communities around the world, the consequences
of climate change aren't a distant nightmare; they're a bleak daily reality.
Inaction has already cost lives.
It’s with those who’ve already been affected that many of us marched and we found hope again. On sunday, something extraordinary happened; the biggest climate march in history took place! 720,000 people, in 175 countries came together to send a clear message to leaders, that the time for inaction is over, that we're here, we're loud, and we're watching.
People took action in lots of British cities too, and London saw well over 50,000 people march, cycle and dance through the streets of the capital.
Below are some of our favourite photos of all the action in
London, Our good friends at 350.org also put together a great selection of
photos of actions from around the world, you can see them here.
50,000+ People! - We had lots of reasons to march
The wonderful Emma Thompson was part of the crowd
All smiles - It was a real carnival like atmosphere in the Greenpeace bloc
The eyes of the world are watching leaders - We made it really obvious
People brought what was important
Loads of people who work in the solar industry joined us too - Many were marching to protect vital subsidies for the solar industry
Tiny heroes joined the party...
And some older ones too
It was a brilliant family day out
Oh yeah! - Thom Yorke came to party!
A giant banner was unfurled just outside downing Street - Reminding this government not to cut vital funding to renewable energy industries
Well it wouldn't be a march without our friend the polar bear!
The beautiful Greenpeace float, just outside the houses of parliament. 
