Wall

Walls are part of gate structures. Walls are the second type of static defense, and you will find them beside the Cannon Towers which surround Gates. They are destructible, and heroes may destroy them to bypass gates. Walls have very low Health and may be killed early on by ranged Heroes which can stand out of the defending tower's range. There are two types of Walls, whose Health differ based on their location on the map. Walls which are beside the Keeps at the Core have increased Health over the ones at your first line of defense near the Forts. Destroying your opponents walls makes them vulnerable to tower dives and will give you early access to destroying their Healing Fountain.

Walls are the only building that Minions will not attack. Usually, enemy wall segments are destroyed indiscriminately, or ignored and left forever. However, they can be useful for a hero like Illidan who can use walls for mobility, like Kharazim who can use it for heals, or like Force Wall Tassadar who can use it for crowd control.

Planed Auto-Destruction
As part of the 2018 Gameplay Updates, the Developers wanted to rework the Wall destruction: Walls should auto-destruct if their connected Towers and Gate are also destroyed.

The auto-destruction of walls was considered because of several reasons:
 * 1) It's unintuitive to have structures that minions will never clean up.
 * 2) Walls provided vision and the developers had no way of communicating this to the playerbase.
 * 3) It promoted degenerative gameplay for Heroes like Illidan, Kel’Thuzad, Chen, etc. who were able to abuse walls when the opposing team has no recourse.
 * 4) On top of this there are situations where these Heroes "needed" these structures to be up in order to perform escapes, combos, etc. and if an ally of these Heroes did the right thing and killed them it became a point of contention amongst team members. It should never be a wrong decision to kill enemy structures.
 * 5) The design intent behind walls is to provide an initial "safe area" for the base region — once the base is no longer safe there's no reason for them to exist.

After reviewing community feedback, the Developers decided to revert this change.