Fun map, though technically illegal. According to page 2 of the FotA rules, Fortress Walls should be built on wall bases, and wall bases should sit on normal terrain tiles (not wall tiles or other 0-height tiles).
The Broken Skyline features five wall bases that start directly on top of the playing surface itself. Despite its technical flaw, The Broken Skyline was accepted as a [URL="http://heroscapers.com/community/showthread.php?t=5725"]Battlefield of Valhalla (BOV)[/URL] map.
To make this version of The Broken Skyline technically correct, use eight of FotA's 13 leftover ground castle pieces to raise all eight wall bases in The Broken Skyline up one level.