Quite a few trenches, fortifications, anti tank ditch,etc...looks like remains of WW2 positions. I think it could be English or Australian defensive positions.
http://en.wikipedia.org/wiki/File:Map_of_siege_of_Tobruk_1942.jpg
http://9thdivvy.blogspot.com/2008/08/map-siege-of-tobruk-1941.html