German Chancellor Angela Merkel is commemorating the 70th anniversary of the liberation of the Dachau concentration camp along with survivors and some of the U.S. soldiers who were there at the time.

Alan Lukens, one of the soldiers who liberated Dachau, recalled Sunday that "it was a terrible shock" to see how badly the surviving prisoners had suffered from disease, malnutrition and ill-treatment. He also remembered the excitement of the inmates as they greeted the liberators with a hand-sewn American flag they had hidden.

Dachau, near Munich, was the first concentration camp set up by the Nazis after Adolf Hitler took power in 1933. More than 200,000 people from across Europe were held there and over 40,000 prisoners died there.

Dachau was liberated by U.S. troops on April 29, 1945.