Edel:
I was just recently in Poland and there are way more things to see than death camps!
Krakow, as mentioned, is a beautiful city, similar to Prague. Visit the Cloth Hall in the old square and the Wawel Castle complex. The castle, museums, and cathedral are fabulous! Sample Wedel candy while you are there and listen for the historic bugle call from the cathedral in the old square that sounds every hour. The royal salt mines are just outside of town and they are outstanding. They even include an underground church and ballroom, complete with chandeliers. English is widely spoken and the big old hotels around the central train station are cheap and safe.
I hope you have a great trip!