US president Barack Obama has been visiting the concentration camp of Buchenwald in eastern Germany. Buchenwalkd was one of the largest and first camps built by the Nazis on German soil – in 1937.An estimated 56,000 people were killed there. His visit was motivated by the fact that his great-uncle was among the US soldiers who liberated the camp in 1945. In a speech at the camp, German Chancellor Angela Merkel reminded the world that the German people will never forget the horrors of the Nazi era and reiterated the importance of Germany’s alliance with the US. The US president had these words: “This place teaches us that we must be ever vigilant about the spread of evil in our time, that we must reject the false comfort that others’ suffering is not our problem and commit ourselves to resist those who would subjugate others to serve their own interests.” Germany is the third leg of Obama’s foreign trip after Saudi Arabia and Egypt. On Saturday, he will attend commemorations in France marking the 65th anniversary of the World War Two D-Day landings.