Those are literally the only three ingredients in some bread I made recently. No yeast, no flavorings, no extra flourishes. Just flour, water and salt. It's the most basic, satisfying bread there is.
How is it made without yeast, you ask? I used a natural leaven I made from flour and water which, after a long period of time and many feedings (of more flour and water) collects natural bacteria from the air (technically another ingredient, I guess) and ferments until it can be used to make bread rise. It's sometimes referred to as a sourdough starter; it's what gives sourdough its characteristic flavor. Though it's a little trickier to use than yeast, you get an amazing flavor, a longer lasting bread (yeast-based breads go stale faster) and an all-around better loaf.