The Third Punic War (149 BC to 146 BC) was the third and last of the Punic Wars fought between the former Phoenician colony of Carthage, and the Republic of Rome. The Punic Wars were named because of the Roman name for Carthaginians: Punici, or Poenici.
The war was a much smaller engagement than the two previous Punic Wars and primarily consisted of a single main action, the Battle of Carthage, but resulted in the complete destruction of the city of Carthage, the annexation of all remaining Carthaginian territory by Rome, and the death or enslavement of the entire Carthaginian population. The Third Punic War ended Carthage's independent existence.
The peace treaty at the end of the Second Punic War required that all border disputes involving Carthage be arbitrated by the Roman Senate and required Carthage to get explicit Roman approval before going to war. As a result, in the fifty intervening years between the Second and Third Punic War, Carthage had to take all border disputes with Rome's ally Numidia to the Roman Senate, where they were decided almost exclusively in Numidian favour.
In 151 BC, the Carthaginian debt to Rome was fully repaid, meaning that, in Punic eyes, the treaty was now expired, though not so according to the Romans, who instead viewed the treaty as a permanent declaration of Carthaginian subordination to Rome akin to the Roman treaties with its Italian allies. Moreover, the retirement of the indemnity removed one of the main incentives the Romans had to keep the peace with Carthage - there were no further payments that might be interrupted.
The Romans had other reasons to conquer Carthage and her remaining territories. By the middle of the second century BC the population of the city of Rome was about 400,000 and rising. Feeding the growing populace was becoming a major challenge. The farmlands surrounding Carthage represented the most productive, most accessible and perhaps the most easily obtainable agricultural lands not yet under Roman control.
The remaining Carthaginian territories were annexed by Rome and reconstituted to become the Roman province of Africa. The site of Carthage was rebuilt and rededicated as a Roman city and would later become one of the main cities of Roman Africa.
That Roman forces then sowed the city and surrounding countryside with salt to ensure that nothing would grow there again is almost certainly an apocryphal story and a 20th century invention. Contemporary accounts show that the land surrounding Carthage was declared ager publicus and that it was shared between local farmers, and Roman and Italian ones. North Africa soon became a vital source of grain for the Romans. Roman Carthage was the main hub transporting these supplies to the capital. The fact that Rome came to rely on North African grain as quickly as she did after conquering Carthage makes any notion that she might have destroyed Carthaginian farmlands quite doubtful.
In January 1985, Ugo Vetere, the mayor of Rome, and Chedly Klibi, the mayor of Carthage, signed a symbolic friendship and collaboration pact, "officially" ending the conflict between their cities.