Thank you all for the recommendations! Chicago is definitely on my list. Now I just need to find the time that some friends and family would go with me that don't mind how long I stay at the museum. I'm just not all that excited about driving in Chicago by myself!
I have been to Mall of America once, but it was years ago. I don't believe we went to the museums in the area, but I don't recall for sure since it was half a lifetime ago.