How far to walk along Mutianyu and how many watch towers?

We walked a section of the Mutianyu wall tdoay and I was wondering if anyone had any idea how far we actually walked as it felt very long but note that it is quoted as only 1.4 miles. We came up the cable car (the enclosed one) and then walked up the wall to the steep part beyond which it said danger, no entry. We then walked back to the slideway. I'm not sure how far this is or how many watch towers? Any idea?
Thanks