65 years ago today American troops liberated some 30,000 starving prisoners being held at the Dachau concentration camp near Munich.

Today’s memorial service at the site of the concentration camp will the first one with Germany’s federal president in attendance. Horst Köhler says he is "thankful to be able to participate." 600 former prisoners and their families have been invited to atttend today’s memorial service. For many of them it will be the first time to visit the place of horror where they were held captive during World War II. In remarks prepared for today’s visit, President Köhler said that "no one can imagine what happens in your soul when you return to the place where you were treated so brutally."

The United States will be represented at today’s ceremony by former American ambassador Alan Lukens, who was part of the 42nd "Rainbow Division" that was the first American unit to reach the camp. Lukens has a message from U.S. President Obama: "It is our mission to honor the legacy of the survivors."

I visited Dachau for the first time in 1972 on a summer study trip to Germany. It was first of four concentration camps I later visited: Bergen-Belsen, Buchenwald, Dachau and Auschitz-Treblinka. You don’t forget places like that.