Today was supposed to be the end of the world as we know it, but as of this writing we seem to still be here. The idea that the world would end came, of course, from a misunderstanding of the Mayan calendar; someone assumed that the date for the ending of a large-scale cycle within the calendar was instead the date for the ending of everything.
Beyond the misinterpretation of the Mayan calendar itself is the question of why anyone would think that an ancient civilization could correctly predict the end of the world. And even if one does think that an ancient civilization could accurately make such a prediction, why limit oneself to the opinion of the Mayans? Did anyone ask what the Incas thought? Or how about the Aztecs? Or what about the Sumerians? Did anyone consult them? Or maybe . . . I don't know . . . the Carthaginians . . . or something . . .