This time it will help your attack , the building is Weapon Depot
It will work just like the safe house (but the weapon depot will increase your attack..)
When you log in to mafia wars 2 you will see the following pop up
Then you get some info about it from a shady person
The mission you get is pretty simple and easy
To finish the weapon depot you will need 2 of each : Black Powder , Ammo Clip , Weapon Crate
Thats it you now have your Weapon Depot in mafia wars 2 :)
Now as you upgrade it you will gain more 3 attack points for each level
Weapon Depot max level is 23 - this will get you 76 Attack! (not confirmed yet)
Here is some photos of the upgrade parts needed to each level and how much defense it gives
(click to zoom!)
Level 1 To 2
Level 2 To 3
Level 3 To 4
Complete screen shots up to level 23 after the jump