Regarding empty space in the periphery of an indoors map and camera placement (tower defense game)

So i am learning the ropes of creating a tower defense game and i have a question regarding the map and the camera. So in the pictures you can see a corridor where the enemies will be moving and you can also see the areas where the guards will be. My question is how do i hide the area outside the walls. Do i just put blackness all around?. Perhaps i just enclose everything with walls?.

Another question is about the camera placement. i am having a real hard time on where exactly it should be and where should it face. Any advice will be really helpful thank you.


You could fill in the empty space with localized volumetric fog