What I learned in Guinea is that we are all responsible for the state of our world. The world - and the system by which we trade, share, cooperate and conflict - is clearly not working. We are only as strong as our weakest members. UNICEF is run at every level by strong, relentlessly energetic, deeply capable people who use that strength, energy and capability to help those who need it most: the weakest, most disadvantaged women and children of our world. All I can do now is help make people aware of what is happening, of what they are doing. That is all that I can do. For now.

I think, actually, that it's a really fascinating time in history because the development of modern technology and the photographs the satellites were taking from space were mapping the earth in a new way, making us feel like the globe we inhabit is much smaller than previously conceived of, in the human mind.

Don’t judge people on who they used to be. Allow them to be who they are now.

With any role, you're extending yourself and acting out things that never happened to you.

All acting is an act of imagination. You are simply conjuring up imaginary circumstances in your mind and responding truthfully to them.

It's like playing tennis, you play a different rally with different people. Every actor is different and the chemistry between actors is different.

Tony Stark in 'Iron Man' helped wider audiences finally embrace the enormous talent of Robert Downey Jr.