Why is Greenpeace important?

Please give me a brief explanation as to why Greenpeace is important? I felt like looking up some organisations that Australia is a part of… Greenpeace came up and after searching the webpage a bit, I couldn’t find any reason (in my head of course) why Greenpeace is important. I am not trying to offend anybody but I was just curious as to why this organisation is important. Please put your full opinion.