9 Lines In The Sand

Hadrian's Wall was a defensive fortification in Roman Britain, begun in AD 122 during the rule of emperor Hadrian. In addition to its military role, gates through the wall served as customs posts. A significant portion of the wall still exists and can be followed on foot along the Hadrian's Wall Path.
Borders, fences, fortifications, demarcations, there are a lot of dividing lines in history. Here are some of the most famous.