I have watched two of his documentaries which I gained a lot of knowledge about the world from. The first is about Year Zero in Cambodia and the second is (as I recall) War on Democracy.
John Pilger came into Cambodia in 1979, and made a documentary about the immediate legacy of the Khmer Rouge regime. He did a really job in bringing causes together with effects. How did Year Zero exist? And what started the fire?
Here is the link 
of his speech: