Pirsumei nisa is the frequently repeated talmudic phrase for what we do on Chanucah. It means publicising the miracle. Pirsumei means to reveal or divulge, and comes from the word paras, meaning spread, as in a tablecloth. (In modern Hebrew, pirsomet is an advertisement.) Nisa is Aramaic for ness, miracle, which also means banner. The underlying connection between banners and miracles is that the latter flag up the usually hidden workings of God in the natural order. Pirsumei nisa is the guiding principle of many Chanucah practices. Lighting the menorah is for pirsumei nisa. We are meant to light it in a place where it will be visible to passersby, eg in our window or outside the door (except in times of genuine persecution), and not more than 30 feet up in the air. We have the shamash candle to use for any secular purpose so that people will know that the Chanucah lights themselves are purely for the sake of pirsumei nisa. This goal of pirsumei nisa goes against the traditional Anglo-Jewish grain of keeping-your-head-down Judaism. The central religious purpose of Chanucah is to let as many people as possible know the miracles of the festival, the miracle of Jewish survival in general and the miracles of Gods hidden presence in the world. Although they have been controversial, Lubavitch-sponsored 15-feet high chanuciot in city centres fulfil this purpose beautifully.