About 1330 in height, nearly 3m blocks. This gigantic size is a consequence of my primary goal which was to outshine all MC builders at least in the field of skyscrapers >:->; the second one was testing the limits of MT as a sandbox building tool. (And this is where they were clearly trespassed). What is interesting, based on my previous experiences with Krasthafen map, which is the largest building project in MT, there is clearly much bigger lag when the engine handles large vertical structures. At first it seemed to be some bug, but then I realized that this must be by all probability caused by the much larger 3D volume full of different blocks needed to get rendered than in the case of apparently much larger but also less volumetric surface maps.
And this is also what makes optimization of commercial games to such awesome results even possible - they all (including Minecraft - this is the main reason why it is going to be kept flat) are essentially mostly 2D smoke&mirrors wrapping over player's eyes, with nothing behind their sheer appearances.