Waarom liggen er in sommige bergpassen kasseien in de bocht?
Zie hier:
https://maps.google.be/maps?q=cernay&hl=en&ll=47.873008,7.128839&spn=0.013458,0.033023&sll=50.88411,4.70543&sspn=0.201653,0.528374&hnear=Cernay,+Haut-Rhin,+Alsace,+France&t=m&z=16&layer=c&cbll=47.87311,7.128516&panoid=Jj3exhc9wCGsyP8hce2YAw&cbp=12,111.58639299999999,,0,0
of ook hier:
https://www.google.com/maps/@50.78167,5.684126,3a,75y,231.65h,90t/data=!3m4!1e1!3m2!1sEisx82_GMjTKufIH2QETVg!2e0