Rome grew from a village to an empire in part because the city was protected from enemy attack. Rome is situated along the banks of the Tiber River about fifteen miles inland from the sea. The Tiber has a ford, or shallow portion near Rome. The ford made it impossible for large seagoing ships to attack the city, but experienced Roman sailors could navigate the Tiber’s waters in smaller ships. Seven hills surround Rome. The hills made it harder for invaders to reach the city and served as lookout areas for the ancient Romans. Rome is also close to excellent farmland and an abundance of wood and stone, so the Romans had the resources to supply a large army.