Former Nazi concentration camp survivor Petro Mishuk of Ukraine mourns during a minute's of silence in memory of the victims at the commemoration ceremonies for the 74th anniversary of the liberation of the former Nazi concentration camp Buchenwald near Weimar, Germany, Thursday, April 11, 2019. On 11th April 1945, units of the 3rd US Army reached Ettersberg Hill. (AP Photo/Jens Meyer)

Former Nazi concentration camp survivor Petro Mishuk of Ukraine mourns during a minute's of silence in memory of the victims at the commemoration ceremonies for the 74th anniversary of the liberation of the former Nazi concentration camp Buchenwald near in Weimar, Germany, Thursday, April 11, 2019. On 11th April 1945, units of the 3rd US Army reached Ettersberg Hill. (AP Photo/Jens Meyer)

Former Nazi concentration camp survivor Petro Mishuk of Ukraine arrives the camp entrance with the slogan 'To Each His Own' (Jedem das Seine) prior to a minute of silence in memory of the victims at the commemoration ceremonies for the 74th anniversary of the liberation of the former Nazi concentration camp Buchenwald near in Weimar, Germany, Thursday, April 11, 2019. On 11th April 1945, units of the 3rd US Army reached Ettersberg Hill. (AP Photo/Jens Meyer)

Former Nazi concentration camp survivor Alexander Bytschok of Kiev, Ukraine, mourns behind a rose during a minute of silence in memory of the victims at the commemoration ceremonies for the 74th anniversary of the liberation of the former Nazi concentration camp Buchenwald near in Weimar, Germany, Thursday, April 11, 2019. On 11th April 1945, units of the 3rd US Army reached Ettersberg Hill. (AP Photo/Jens Meyer)

Former Nazi concentration camp survivor Alexander Bytschok of Kiev, Ukraine, mourns on a metal plaque during a minute of silence in memory of the victims at the commemoration ceremonies for the 74th anniversary of the liberation of the former Nazi concentration camp Buchenwald near Weimar, Germany, Thursday, April 11, 2019. The metal plaque bearing the names of fifty nations in alphabetical order is inserted in the ground. The middle section is kept at 37?o C, the temperature of the human body. On 11th April 1945, units of the 3rd US Army reached Ettersberg Hill. (AP Photo/Jens Meyer)

11 April 2019, Thuringia, Weimar: The former prisoner Petro Mischchuk from the Ukraine kneels on the former roll call square during a minute's silence at the time of liberation at a commemoration ceremony marking the 74th anniversary of the liberation of the former Nazi concentration camp Buchenwald. Photo: Martin Schutt/dpa-Zentralbild/dpa

11 April 2019, Thuringia, Weimar: Contemporary witnesses take part in a commemoration ceremony on the 74th anniversary of the liberation of the former Nazi concentration camp Buchenwald at the time of the liberation on the former roll-call square. Photo: Martin Schutt/dpa-Zentralbild/dpa

11 April 2019, Thuringia, Weimar: Contemporary witnesses take part in a commemoration ceremony on the 74th anniversary of the liberation of the former Nazi concentration camp Buchenwald at the time of the liberation on the former roll-call square. Photo: Martin Schutt/dpa-Zentralbild/dpa

11 April 2019, Thuringia, Weimar: A rose lies on a new commemorative plaque for Dietrich Bonhoeffer on the day of a commemoration of the 74th anniversary of the liberation of the former Nazi concentration camp Buchenwald. Photo: Martin Schutt/dpa-Zentralbild/dpa

11 April 2019, Thuringia, Weimar: Contemporary witnesses take part in a commemoration ceremony on the 74th anniversary of the liberation of the former Nazi concentration camp Buchenwald at the time of the liberation on the former roll-call square. Photo: Martin Schutt/dpa-Zentralbild/dpa

11 April 2019, Thuringia, Weimar: The former prisoner Petro Mischchuk from the Ukraine kneels on the former roll call square during a minute's silence at the time of liberation at a commemoration ceremony marking the 74th anniversary of the liberation of the former Nazi concentration camp Buchenwald. Photo: Martin Schutt/dpa-Zentralbild/dpa

11 April 2019, Thuringia, Weimar: A stele with the inscription "Buchenwald" stands on the former roll-call square, recorded on the day of the commemoration of the 74th anniversary of the liberation of the former Buchenwald concentration camp. Photo: Martin Schutt/dpa-Zentralbild/dpa

11 April 2019, Thuringia, Weimar: "Jedem das Seine" stands at the camp gate, recorded on the day of the commemoration of the 74th anniversary of the liberation of the former Buchenwald concentration camp. Photo: Martin Schutt/dpa-Zentralbild/dpa

11 April 2019, Thuringia, Weimar: The former prisoner Petro Mischchuk from Ukraine holds a rose in his hand at a commemoration ceremony commemorating the 74th anniversary of the liberation of the former Buchenwald concentration camp in the former roll-call square. Photo: Martin Schutt/dpa-Zentralbild/dpa

11 April 2019, Thuringia, Weimar: The Buchenwald survivor Eva Fahidi-Pusztai holds a rose in her hand at a commemoration ceremony commemorating the 74th anniversary of the liberation of the former Buchenwald concentration camp on the former muster ground. Photo: Martin Schutt/dpa-Zentralbild/dpa

11 April 2019, Thuringia, Weimar: Red and white roses lie at a commemoration ceremony for the 74th anniversary of the liberation of the former Buchenwald concentration camp at a memorial plaque on the former roll-call square. Photo: Martin Schutt/dpa-Zentralbild/dpa

11 April 2019, Thuringia, Weimar: A stele with the inscription "Buchenwald" stands on the former roll-call square, recorded on the day of the commemoration of the 74th anniversary of the liberation of the former Buchenwald concentration camp. Photo: Martin Schutt/dpa-Zentralbild/dpa