Murals sprout out of walls like weeds sometimes. One day, the wall is empty and boring and the next it's covered with an elaborate work of art by a mysterious painter. Fintan Magee shared these photos from the making of his "The Artifact" mural in Bogota that sort of answer the question "how'd he do that?" The photos show the wall at various stages of Magee's process, from sketch to completed piece. Not all mural artists work from sketches, but it's pretty cool to see one artist's method for completing the daunting task. It makes the finished product even more impressive in our opinion.