I see the exhibition is running until January 10th, I'm sure you will be going back for another look - I always find that when I re-visit an exhibition you always find something new. I find looking at work like this very inspirational & very humbling, you might also like looking at:
http://www.artphotogallery.org/02/06/salgado01.html Sabastiao Salgado from Aimorés, in the state of Minas Gerais, Brazil, is one of the world's greatest photographers.
Thanks Peter! Yes, I want to go back for a new look. I agree with you, every time I look back, I discover something that had not seen yet. Thanks for the link. Sebastião Salgado is wonderful. His works are always in evidence here!