Hannibal led his army in the legendary crossing of the Alps and defeated army after army sent to stop him by Rome. But no one was able to recover better from a loss than the Romans and they survived and withstood Hannibal's campaigns for years. After clearing the Carthaginians out of Iberia, Scipio led a Roman army to Africa, to stop the Carthaginians on their home turf. Ultimately failing in his attempt to destroy the Romans, Hannibal had to be recalled home. Scipio Africanus earned his name and defeated Hannibal on his home turf, leading to the surrender of Carthage. 

Now with total control of the Western Mediterranean, the Romans turned to the East. Over the course of four wars, they expanded their control over the Greeks integrating their territory and then their culture, into their growing empire. 

The expansion of this empire led to massive influxes of wealth, helping the elites in Rome to grow massively rich. The growing divide between rich and poor led many Romans into destitution. Against the conservative Optimates, other politicians, called Populares, began to clamor for land redistribution and help for the poor. The Optimates violently resisted reforms and force began to be used in place of law. The ingredients for civil unrest were in the pot and with Marius and Sulla, they would boil over into open civil war.