Rome was purposely built on 7 hills. The hills were steep as a defense for Rome so it would keep enemies out. The hills also made it easier for the citizens to defend the city from attack. The government will have more time to prepare and to get ready for a fight.
Rome had Alps and Apennines. Rome would not split up into small isolated communities. Italy had better farmland than Greece. Their mountain slopes leveled off to flat plains that are really good for growing crops. Italy could grow more food so, Italy could have a bigger population than Greece can have. If the population grows the government will get more money from taxes.
Rome was very close to the Tiber River from the Mediterranean Sea. The Tiber River gave the Romans a water source and a route to the rest of the Mediterranean world. Also Rome was located in a place where people could cross the Tiber River easily. Rome became a place for people to stop while traveling north and south in western Italy and a center for merchant ships to stop and sell goods when they were sailing into the western Mediterranean. Also it mad it easier for them to trade. Trading will help the government better because they can now work with other countries and get more/better things.
Po Valley is a huge area of Italy and is about 400 miles long. The valley is made up of both plains and hilly areas which eventually lead out to the mountain ranges. This area had very fertile land that was used to grow crops for the citizens. Many people live in the Po Valley and and it became the industrial center of Italy. The Po River flows through the basin and helped to create the fertile land the people lived off of. The government and the people will have a bigger population.