Towers - are the still effective without walls

basbug

Newcomer
Hello,
I believe I read a guide long time ago, but I want to make sure... scenario:
-Bireme City
-Build Tower and bring the wall to zero
will the tower still be effective and give the birs 10% bonus in defense?

I read some posts here and there that suggests either responses.
BTW, the simulator suggests that tower without a wall gives the defense bonus.

Thanks in advance