When I was a teenager, I lived in Turkey for 3 years. One of the advantages was the travel. Everything is very close and easy to get to. We went to Munich and visited Dachau. I agree with Craig58. All you have to do is visit and you will know it really happened.
The thing to remember is that it wasn't just the Jews that were killed in these camps. The Jews were the largest portion, but also many Catholics were killed (i.e. Maximillian Kolbe), even the beloved John Paul II had to go underground to finish seminary. Gypsy were another large group that were killed in these camps.
I can remember how quiet everything was around the camp. Birds didn't even sing around Dachau. There were a group of German students there the day we were there. By the end of the day, every one of them had broken into tears, the pain and anguish was quite evident on their faces. My mother could not go very far into the camp, she became so upset, and she is farm girl from Tennessee.
My husband is German, his mother came to the US as a "war bride" after WWII. She has told me stories about the propaganda that was spread about the Death Camps. Incredible stuff.