Mauthausen-Gusen concentration camp . Mauthausen concentration camp (known from the summer of 1940 as Mauthausen-Gusen concentration camp) grew to become a large group of Nazi concentration camps that were built around the villages of Mauthausen and Gusen in Upper Austria , roughly 20 km east of the city of Linz . __http://en.wikipedia.org/wiki/Mauthausen_concentration_camp__