Tens of thousands of protesters took part in a climate change march on Brussels as a United Nations summit on keeping global warming in check began in Poland.
Belgian police said some 65,000 people participated in the 'Claim the Climate' demonstration on Sunday.
Protesters marched through the Belgian capital near to the European Union headquarters with banners bearing slogans including 'There is no planet B' and 'Climate First, Politics Second'.
One man dressed up as a penguin holding a sign that read 'I need my fridge' and another group carried a giant inflatable replica of the globe as they marched.
The organisers of the protest called for ambitious climate policies to limit global warming to one-and-a-half degrees Celsius in line with goals set by the Paris Agreement in 2015.
Belgium's Prime Minister Charles Michel called the march 'a formidable success' and promised to defend the 'ambitious targets' at the two-week-long COP24 conference which began in Katowice, Poland on Sunday.
Key talks began a day earlier than expected, with four senior figures behind the efforts to limit climate change warning that the Earth is now 'at a crossroads', the BBC reported.
The four former UN climate talk presidents called for action when the 24th Conference of the Parties to the United Nations Framework Convention on Climate Change (COP24) prematurely convened.
A statement issued by Frank Bainimarama of Fiji, Salaheddine Mezouar of Morocco, Laurent Fabius of France and Manuel Pulgar Vidal of Peru said: 'Decisive action in the next two years will be crucial.
'What ministers and other leaders say and do in Katowice at COP24 will help determine efforts for years to come and either bring the world closer to meeting the goals of the Paris Agreement - including protecting those most vulnerable to climate change - or push action further down the road.'
Read more: Tens of thousands of protesters take part in Brussels climate change march as UN Summit of 200 nations gets underway in Poland