Auschwitz is within range, but I'd offer a word of caution about going there as a tourist. It is a truly terribly disturbing experience, which we should probably all expose ourselves to at some stage, but I think one needs to prepare, mentally, for going there. It's a very sobering experience and I've seen grown men visibly shaken.
On a happier note the Polish salt mines are what I remember most. Incredible caverns with carved halls and chandeliers, all etched from salt. Extraordinary.
Have a great time... Oh yes; Just remembered something else, Buffalo snaps.. a Polish vodka flavoured with herbs and 'buffalo or bison grass'...!
Suprised I remember that actually