How i break walls on sea made by land troops?

I have no idea how. Is it even possible to break it?
PS: in a map without planes

If you get the angle and positioning just right, you should be able to break it with both naval and ground units - at least naval units have usually worked for me so far. Try to get close with some naval units and then play around until they are drawn into attack. Hope it works for you too!

Attack the center of the wall by using ships. Sometimes the wall is too small or blocked by another wall and becomes unbreakable.