Visiting Frankfurt, Germany in March. What sites should I see?

[deltaspecialforce]

Hey folks. I'm headed to Frankfurt for business in March. I will have some free time but probably not enough time to get too far out of the city.

Does anyone have any suggestions on where I should go to see some historic WWII or TR locations, memorials, etc? I visited Munich in 2012 and was able to catch a bus to Dachau which was a very moving experience. Anything like that available around Frankfurt?

Thanks! Also, I will take suggestions on places to eat and drink as well