After his sister died of brain cancer, Japanese artist Motoi Yamamoto began constructing enormous, detailed labyrinths. They're temporary installations made out of ground salt and reflect a special significance that his culture places on that mineral:
In Japanese culture salt is not only a necessary element to sustain human life, but it is also a symbol of purification. He uses salt in loose form to create intricate labyrinth patterns on the gallery floor or in baked brick form to construct large interior structures. As with the labyrinths and innavigable passageways, Motoi views his installations as exercises which are at once futile yet necessary to his healing.
http://halsey.cofc.edu/exhibitions/2006/05_fon/09_yamamoto01.html via Dude Craft | Artist's Website