Auschwitz-Birkenau ( Konzentrationslager Auschwitz (help·info)) was the largest of Nazi Germany's concentration camps. Its remains are located in Poland approximately 50 kilometers west of Kraków and 286 kilometers south of Warsaw. The camp took its name from the nearby town of Oswiecim. Birkenau, the German translation of Brzezinka, refers to the many birch trees surrounding the complex. Following the German invasion of Poland in September 1939, Oswiecim was annexed by Nazi Germany and renamed Auschwitz, the town's German name. Up to then, there had been no special significance attached to the name; for example, "Duke of Auschwitz" was for centuries one of the minor titles held by the Habsburg Emperors (see Francis II), which at the time was completly innocuous and unimportant. The camp commandant, Rudolf Höß, testified at the Nuremberg Trials that up to 3 million people had died at Auschwitz. The Auschwitz-Birkenau State Museum has revised this figure to 1.1 million, about 90 percent of whom were Jews from almost every country in Europe. Most victims were killed in Auschwitz II's gas chambers using Zyklon B; other deaths were caused by systematic starvation, forced labor, lack of disease control, individual executions, and purported "medical experiments