This secret area is easier to find on old school mode. (THIS WORKS BETTER WITH SOME LOUD MUSIC!) There is a tall building in the middle of the map right across from the place where a building with a automated machine gun. Go to the window where there is a ladder. Jump from the window to the box with the ladder. Climb ladder and at the top you will get a 360 degree areal view of the place. I will put a pic later.