1,123,960 blocks to be exact, all placed by hand. Things like this are usually built with a help of a software, converting the art into Minecraft blocks. But not this one.
The creator Thorlar livestreamed the whole process—23 weeks—as he slowly transformed the empty map into the trio of Kerrigan, Diablo and Deathwing.
You can zoom in and out (and search for tiny errors) here.