"Many years later, as he faced the firing squad, Colonel Aureliano Buendia was to remember that distant afternoon when his father took him to see ice." Of course the first thing you're wondering is what brought Buendia before the firing squad to begin with, and, more importantly, if he's going to get out of it, and how. (It doesn't seem likely that an author is going to introduce a character just to kill him off.) But then, frustratingly, Garcia Marquez starts talking about going to see ice. You're left hanging, your mouth open. "No, wait!" you want to cry. "What about the firing squad?"
But that part is fascinating too. "Every year during the month of March a family of ragged gypsies would set up their tents near the village, and with a great roar of pipes and kettledrums they would display new inventions." They show the villagers magnets and telescopes, magnifying glasses and false teeth. And finally, one year, they open a chest: "Inside there was only an enormous, transparent block with infinite internal needles in which the light of the sunset was broken up into colored stars…'It's the largest diamond in the world.' 'No,' the gypsy countered. 'It's ice.'"
Writing teachers and books about writing will tell you that your first sentence has to hook the reader in some way, draw them in. But this first sentence isn't anything as weak as a hook. It's more like a giant wave rushing you along -- you can't stop reading. And of course Garcia Marquez returns to the firing squad several times, and you do eventually find out what happened.
It's also Garcia Marquez introducing us to his method of story-telling. Ordinary things, like ice, take on the patina of the marvelous. And marvelous things, like a woman being carried off by butterflies, are recounted as if they're everyday occurrences. It's an amazing balancing act -- and it goes on, perfectly, for 380 more pages.
(I used to admire the juxtaposition of "fire" and "ice" as well, but unfortunately I later discovered that this doesn't work in the original Spanish, that "peloton de fusilamiento," is more like "shooting squad." Oh, well, It's still brilliant.)