Wall are the Main fortification for your defense and capable of tanking damage from enemy but enemy usually choose to turn around if there are entrance nearby within a range of their attack but units like healer dragon and balloon usually pass thru since they can fly through them and some ranged unit like archer and Mage can attacking trough the wall , wall is the favorite target of skeleton wall breaker since the deal 40x damage to them here's the list of walls with its level. Every time you successfully upgraded the town hall your Fence/Wall capacity increased by 25
Level.1
Cost:200 Armor:300 Looks like a wooden sharp fences
Level.2
Cost:1.000 Armor:500 A bare stone wall
level.3
Cost:5.000 Armor:700 Tidy looking concrete wall
level.4
Cost:10.000 Armor:900 Same with before but darker and taller
level.5
Cost:30.000 Armor:1.400 Made of shiny gold