We visited Mauthausen, the site of a concentration camp during World War II. On August 8, 1938, five months after Austria was "annexed" by the Nazis the first inmates arrived at the camp. Between 1938 and 1945 190,000 people were sent here. At least 10,000 were murdered in the gas chamber. At least 90,000 people died at the camp.

I have never been so moved. I couldn't breathe. I couldn't speak. I couldn't take pictures of anything other than the things that have grown there - in this sacred earth. The signs of life that have appeared at the site of so much death.

How can human beings do those things to other human beings? We must never forget that, as a species, we are capable of atrocities - lest we repeat ourselves.