We had a nice long weekend in Krakau, Poland. And we visited the concentration camps of Auschwitz. Horrible.
In case you didn't know: Auschwitz consists of 2 complexes, the first camp near the town, and the larger camp Birkenau, some 3 km away. Especially the latter was horrifying.
An impression of rows of chimneys on the vast terrain, the only thing left of the endless barracks after they were set on fire to be burnt down.