Oswiecim in Polish. Prussia, the Austro-Hungarian Empire and Russia divided Poland up among themselves on more than one occasion. So many of their cities have a Polish name and a German name.
I knew a guy once who was a German soldier in WWII. He was captured by the Allies and ended up in a Western US POW camp. He was from Silesia, which had been German with lots of Poles living there for centuries but is now part of Poland. He saw what was going on at the end of the war and lied about where he was from, going West. Someone he befriended in the camp ended up sponsoring him to emigrate to America.