Visa necessary for US citizen to enter Beijing for seven hours between flights?

If you have onward air ticket and visa (if necessary) for the third destination, you needn't apply one for your Great Wall trip.

Thank you, Lucy. So, I just have to carry my passport and ticket back to Chicago, and the authorities will let me leave the airport? Any suggestions for the short time I have?

Yes, you are ok with your passport and ticket for returning USA. Honestly, 7 hours is too short for you to visit some attractions in Beijing.

Thanks again, Lucy. I know seven hours isn't much, but it is all I will have. So, I will dash to The Great Wall. From what I have read, I will be able to get there and back in under two hours, which means I will have at least a few hours to spend at The Great Wall.