The Impregnable Fortress

I was bored and i decided to build a giant minecraft dam, cause i saw some cool dam vids on youtube.
So this is the result, an Impregnable Fortress

Feautures
Notice: This fortress should not be beautiful, anyway its practical. There are lava gates, the walls are very thick, lava traps on every stairway and chests on every layer for lava buckets and arrows.

Updates
Maybe i'll add a town and a harbour too. The fortress is too far away from spawn. I'll fix that soon.