Tallest possible structure in Minecraft

Although Minecraft is designed to allow as much creative freedom as possible, there are some restrictions. Structures cannot exceed 256 blocks in height – owing to the fact that each world is made of “chunks” measuring 16 x 16 x 256 blocks. However, in order to build that high, construction must begin immediately above each world’s bedrock layer. In other words, mega-builders will need to go down before they can go up...