From OpenStreetMap Wiki
|barrier = city_wall|
|A city wall, a fortification used to defend settlements in ancient to modern times|
|Used on these elements|
|Tools for this tag|
A city wall is a fortification used to defend a city or settlement from potential aggressors. In ancient to modern times, they were used to enclose settlements.
How to map
|barrier=city_wall||Behaves same as natural=cliff, that is no crossing as left-right are different height. |
Lower side on right side of way direction, marked with dots.
|both sides same height, marked with dots on both sides.|
Use historic=yes for historic city walls.