Complex sentence: The worst damage was in the central business district, with many buildings entirely destroyed; the affluent residential area to the south was substantially diminished, but the tornado left houses untouched here and there immediately adjacent to houses which were flattened.
Split into simpler sentences: The worst damage was in the central business district, with many buildings entirely destroyed. The affluent residential area to the south was substantially diminished, but the tornado left houses untouched here and there immediately adjacent to houses which were flattened.