People do all kinds of awful things to this classic Andalusian soup. I've had it made with ketchup, cream of tomato soup, and hot sauce. I've had it served so cold that it's almost ice cream, and left out so long that it begins to ferment. I've had it garnished with chopped hard-boiled egg, minced onions, and tortilla chips. I've even had it made without bread, which to me means that it wasn't even really gazpacho at all. This is the way I learned to make gazpacho years ago in Jerez de la Frontera.
Stir vinegar into 1 cup of ice water, then put the bread into a bowl and add the mixture. Let the bread soak for 20 minutes.
Halve the tomatoes crosswise and scoop the seeds out with your finger. Holding a tomato half in the palm of your hand with the cut side facing out, gently grate it on the large holes of a 4-sided grater set into a large bowl. Discard the tomato skin when the flesh has been grated. Repeat the process with the remaining tomatoes.
Combine tomatoes, bell pepper, garlic, olive oil, and soaked bread with any liquid that remains in a blender, then season the mixture generously with salt. Purée the mixture until smooth, then pass it through a food mill or sieve to remove any remaining tomato seeds.
Put gazpacho into a large pitcher, cover, and refrigerate for about 2 hours. Serve in tumblers or decorative glasses.