Which city did Rome destroy at the end of the Third Punic War?

Rome destroyed Carthage in 146 BC, ending a rivalry that had run through three wars over more than a century. Carthage was a Phoenician colony on the North African coast that had grown into the dominant trading power of the western Mediterranean, and the first two wars had already stripped it of Sicily, Spain and its navy, and left it paying a heavy indemnity. By the third war it was no strategic threat at all, but a faction in the Roman senate, associated with Cato the Elder, pressed relentlessly for its elimination anyway, arguing that a recovering commercial rival could not be tolerated. Rome imposed demands designed to be refused, besieged the city for three years, and took it street by street, killing or enslaving the population and razing the site. Rome later refounded a colony there, and it became one of the great cities of the empire.

The story that Rome sowed the ground with salt is a much later invention with no ancient source.