The Third Punic War was the inevitable result of treaty that was too restrictive and a long standing feud that couldn't be mitigated.
After defeat in the Second war in 202 B.C, Carthage was prohibited from attacking any friend of Rome and also required to pay reparations to the victor. But, over time, the Roman Senate saw hawk and dove factions emerge during arguments over the future of Carthage. The Punic council, looking at Rome from a position of weakness, saw similar factions argue over the risk of provoking their longtime adversary. Adding to the mix, neighbors of the Carthage began to attack her thinking she would not fight back. But she did and finally, in 149 B.C, the efforts Carthage made to protect herself were seen as violations by the hawks in the Roman Senate and war was declared.
The years of 149-148 B.C, were unsuccessful from the Roman standpoint as multiple attempts to assault the city failed. Then, after Scipio Aemilianus was elected consul in late 148, he proceeded to Carthage intent on finishing the war. Aemilianus spent the summer of 147 B.C. getting his army in shape and then in the fall built a double wall 3.2 miles across the Isthmus separating the city of Carthage from the rest of the Tunisian Peninsula. The inner wall would starve the Carthaginians into submission while the outer wall served to protect the Roman army from being attacked from behind. The inner wall was twelve feet high with parapets and towers. A central tower was high enough to provide a view into the city.
To help you understand the geography involved in this battle, I have constructed the following map which shows the city of Carthage and its critical landmarks.
Aemilianus came to realize, soon after the siege began, that closing the land route to Carthage was only a partial solution because the Carthaginian port was still open. Moreover the Carthaginian commander, Hasdrubal, had his army stationed between the city walls and the port (labeled 2 on the map). Aemilianus wanted to move Hasdrubal so he created a distraction by sending a night raiding party of 4,000 to an area north of the Utica Gate, labeled 1 on the map, where scaling the wall was easier. The raiders had free reign over wealthy neighborhoods and an alarm went up immediately.
When Hasdrubal got word of the attack, he abandoned his position at 2 and brought his army back inside the city walls to counter the Romans, but they abandoned their positions the same night and retreated. The Romans overran the vacated position 2 and moved on to position 3 where they could devise an attack on the port. Meanwhile, parallel trenches were dug close to the city was with cross trenches connecting them. The trenches were filled with sharpened spikes.
Next, the Roman army began to construct a “mole” or sea wall to block the entrance to the commercial harbor (labeled 4). The mole was ninety six feet wide at the bottom, twenty-four feet wide at the surface, and constructed of heavy stones. The Roman army worked twenty-four hours a day on the construction until the mole was completed.
When the Carthaginians saw what the Romans were up to, they began a desperate construction project of their own to make a hole in the seaside wall of the commercial harbor so their ships could escape to the sea. The location of this hole was between 4 and 5 on the map. Since the majority of the project was conducted under cover, the Romans were unaware of what the Carthaginians were doing until 50 Triremes from the Carthaginian fleet emerged through the newly created opening. A more resourceful commander could have used the element of surprise to inflict a great deal of damage on the Roman fleet but the Punic commander was content to make a parade of his ships and engage in some training exercises before retiring for the night. When they emerged again three days later, the Roman fleet was prepared for battle. In the confusion of ships, the opening into the harbor was blocked by ships so the Carthaginians had to tie up along the outer break wall and absorb repeated Roman attacks. By nightfall they were able to return to the harbor. Before the end of the campaign season, the Romans attacked and took control of the outer break wall but put off attacking the city to direct their attention to raids on the interior and wait for the end of the year elections. With his choke hold on the city in place, Aemilianus knew it was just a matter of time before the city would starve.
During the spring of 146 B.C, Aemilianus returned to Carthage to finish the job. The final assault was focused on a point near the military harbor labeled 5 on the map. The Romans fought their way over the wall and despite Hasdrubal’s attempt to block them by setting fires, they were able to work their way into the city. The Carthaginians retreated to their citadel at Byrsa shown (rectangle on the map). The citadel was on top of a hill and between that point and the harbor sat three or four blocks of multi-story apartment buildings, so, in order to reach the citadel, the Romans had to engage in the worse kind of urban combat imaginable. Aemilianus ordered the neighborhood to be set on fire and the conflagration lasted for six days.
At that point, 50,000 civilians from the citadel where allowed to leave and be delivered into Roman hands to be sold as slaves, while Roman deserters and the remainder of Hasdrubal’s army fought on. But it wasn't long before the Punic general surrendered and threw himself at the mercy of the Romans. We know nothing of his fate other than he was paraded in Rome during the triumph celebrating the end of Carthage. The city itself was leveled and salt was poured on the arable land to prevent its use. No doubt this was the residue of hatred the Romans felt for Carthage going back to the time Hannibal embarrassed them during the second war.
Later Carthage would have a new life when Julius Caesar built a colony there in the mid-40s B.C. By the first century A.D, Carthage would become the second largest city in the western empire.