My first reaction was: "MY ancestors? I don't think MY ancestors would have wasted their time on something like that..."

But then I remembered a line from the old Kung Fu series:

"Grasshopper, Just because you do not understand somebody else's purpose does not make THEM crazy or stupid..."

Which is good because, my next thoughts was: "Ummm, I think I do have a lot of ancestors from that region. Maybe one of them did help to build that ..."

OK, sorry... Back to bikes...