What does a gunshot sound like?

I teach in a school in a neighborhood with an unfortunate level of gun violence. After school the other day I was working in my classroom and there were two loud bangs from outside, sort of like the sound two wooden boards might make if you clapped them together really hard, only louder. No one else (eg, the other teachers inside or people out on the street) seemed worried, so I figured it was just a car backfiring or something. But it was loud enough to make me wonder.