Final answer:
The Strait of Messina is the waterway that separates Sicily from the Italian mainland, about 2.5 miles wide at its narrowest point.
Step-by-step explanation:
The strait that separates Sicily from mainland Italy is known as the Strait of Messina. It is about 2.5 miles wide at its narrowest point and serves as the natural boundary between the island of Sicily and the Italian Peninsula.
Steeped in history and of significant strategic importance, the Strait of Messina has influenced the cultural and economic exchanges between the regions it separates, playing a pivotal role in various historical events.