Rome is near the central western coast of Italy on the banks of the Tiber river. Because Rome is located on a river and is close to the coast of the Mediterranean Sea, Rome was positioned in such a way to be able to export its goods easily and to import the goods of others easily. Also, the central location of both Rome and Italy in the Mediterranean put Rome in an ideal position to have contact with Spain, France, Greece, and Egypt.
We should also not forget the famous seven hills of Rome that surround the city. These hills, along with the Tiber river, provide natural defences for the city. Additionally, the Appennine Mountains, which run north and south down Italy's length give Rome protection from the east, while the Alps protect Rome from invasion from the north.
Thus, a combination of natural defenses, natural resources, and relatively easy access to the sea helped Rome dominate the Mediterranean for a thousand years.