People build all kinds of things in Minecraft, from houses, to massive buildings, to entire fantasy realms. Today is the first time I've ever seen an entire country modeled in the game, and it's a 1:1 scale!
This model of Denmark takes up approximately 4000 billion blocks, and over a terabyte of disk space. The model was produced using publicly available information - such as satellite photos, maps, and more - to generate the map as accurately as possible. Originally designed for use in classrooms, this amazing map can be downloaded in 10 square-kilometer sections, just in case you don't have the drive space for the whole country.