Short answers, pulled from the story.
The Punic Wars were three conflicts fought between the Roman Republic and the Carthaginian Empire between 264 and 146 BC. They involved forty-three years of warfare across the western Mediterranean, spanning Sicily, North Africa, Iberia, and mainland Italy.
The First Punic War began in 264 BC over control of the Sicilian city of Messana. Rome's expanding presence in Italy brought it into conflict with Carthage's dominance over much of Sicily. Polybius, the most reliable ancient source, concludes both sides stumbled into war more by accident than design, with neither anticipating a prolonged conflict.
Hannibal left New Carthage (modern Cartagena) in May or June of 218 BC with an army including 37 war elephants. He crossed the Rhone, evaded a Roman fleet at Massalia (modern Marseille), and crossed the Alps in 24 days, arriving in the Piedmont region of northern Italy in early November with 20,000 infantry, 6,000 cavalry and surviving elephants.
At Cannae in 216 BC, Hannibal's army surrounded a Roman force of 86,000 men by letting the Roman infantry push through a deliberately weak centre, then swinging Libyan infantry around the Roman flanks while Carthaginian cavalry encircled them from behind. At least 67,500 Romans were killed or captured, making it Rome's greatest military disaster of the war.
The treaty agreed in 201 BC stripped Carthage of all its overseas territories and some of its African ones, required an indemnity of 10,000 silver talents to be paid over 50 years, limited the Carthaginian fleet to 10 warships, banned war elephants and prohibited Carthage from waging war without Rome's express permission. Scipio, who dictated the terms, was awarded a triumph and the honorary name Africanus.
Rome declared the Third Punic War in 149 BC after Carthage raised an army to defend itself against repeated Numidian encroachments, which Rome used as a breach of the 201 BC treaty. After a three-year siege, Roman forces under Scipio Aemilianus stormed the city in 146 BC over six days of street-by-street fighting. The survivors, estimated at 50,000, were sold into slavery and the city was completely demolished.