Three days later a great battle was fought at sea. From morning until evening the battle raged, but neither side could claim the victory. At length the Carthaginian fleet attempted to sail back to its harbour. But the smaller vessels blocked the passage so that the large ships were forced to stay without. The Romans seized their chance, and attacked the enemy in this position. A desperate struggle followed, and the Carthaginians, who were as used to the sea as to the land, fought with unfailing courage. But at length they were beaten, and the greater part of the new fleet was destroyed. Winter was approaching, and Scipio had at length succeeded in closing every approach to the city. Neither by sea nor by land could the wretched people now get food. As the weeks dragged slowly by, the misery in the besieged city grew terrible. Many of the citizens killed themselves rather than endure a day longer the pangs of hunger, while others in their desperate need even ate the dead bodies of their fellows. Some gave themselves up to the Romans, and were then sold as slaves. In the early spring of 146 B.C. the Carthaginians were so exhausted that they had little strength left to withstand the attack which Scipio now made upon the town. Yet still they would not yield. Hasdrubal, seeing that the enemy could not be repulsed, ordered the outer harbour to be set on fire. But as the flames leaped up, Lælius succeeded in scaling the wall, and entered the city with his men, unnoticed in the confusion caused by the fire. They soon reached the gates, and opened them to their comrades, and in a short time the Forum was in the hands of the Romans. From the Forum, three narrow streets led up to the Byrsa or Castle of Carthage. The houses on either side of these streets were six storeys high, and to these the inhabitants of the city rushed. As the Romans pushed their way along the narrow streets, the Carthaginians flung down upon them from windows and roofs every missile or weapon on which they could lay their hands. At length Scipio ordered his men to storm the houses. Then a terrible hand-to-hand fight began with the starving citizens. Clambering on to the roofs, which were flat, the soldiers stretched boards or beams across from one house to another, and hurled out of the way those citizens who still tried to hinder their progress. For six days and nights the desperate townsfolk continued to baffle the efforts of the Romans to reach their last stronghold, the Byrsa. During this awful struggle, Scipio himself sent forward continually new companies of men, and in his anxiety he scarcely found time to sleep or to eat. At length, however, the foot of the citadel was reached, and Scipio ordered the narrow streets to be set on fire. Then the Carthaginians knew that they could do no more, and those who had taken refuge in the Byrsa surrendered, on being promised that their lives should be safe.