I just finished a 12.401km run that lasted about 1hh:5mm:51ss !
I wanted to do a longer run but I needed to take a road that is dangerous by foot (cars are fast there) or I needed to do 8 more kilometers to go home with a different path. So I just called someone that came to get me by car.
It was in any case a beautiful run around a stone quarry (it was not just around it but I could see it sometimes during the run). You can see on the picture all the machines. I will probably keep this circuit for other times!