The defenses were designed to prevent interference or intrusion into the life of the Romans. Behind them the inhabitants constructed temples, a forum, palaces and other public buildings, bringing in clean mountain water by an aqueduct that eventually reached a length of 44 miles, constructing an extensive system of drains and sewers that disposed of city wastes, building a network of roads that eventually gave the Romans access first to all parts of Italy and later to the entire Mediterranean Basin. They also replaced the wooden bridges over the Tiber and other rivers by stone bridges carried on stone piers and arches. Early in their building activities the Romans learned to make a cement so weather-resistant that many of their constructs are still usable two thousand years after the Romans built them. These and similar building operations made Rome one of the show places of the Graeco-Roman world. They also provided for the Romans a level of stability and security far beyond that of their neighbors in that part of the unstable Italian peninsula. At the time Rome was founded, presumably about 700 B.C., the Italian peninsula was occupied by a large number of principalities, kingdoms and tribal nomads, newly arrived from eastern Europe and Asia. The struggle for pasturage and fertile soil, for dwelling sites and trading opportunities, went on ceaselessly. Romans, like their neighbors and competitors, were reaching out to provide themselves with food, building materials, trade opportunities, strategic advantages. They expanded peacefully if possible, using diplomacy up to a certain point and only engaging in war as a last resort. But since the entire Italian peninsula was occupied by more or less independent groups, each of which was seeking a larger and safer place in the sun, the outcome was ceaseless diplomatic maneuvering, using war as an instrument of policy in the struggle for pelf and power. Four centuries of power struggle, in which Romans played an increasingly prominent role, gave the Roman Republic and its allies substantial control of the entire Italian peninsula. Beginning as one among many small independent states in Italy, the inhabitants of Latium emerged from four centuries of competitive diplomatic and military struggle as the de facto masters of all Italy. Power struggles are carried on by contestants who occupy a particular land area with its resources and other advantages. Latium was small in extent (some 2,000 square miles) and had very limited natural advantages. Operating from this restricted base, through four centuries of diplomacy, intrigue and war, the Romans enlarged their base of operations to include the whole of Italy. In this crucial era of its history Rome expanded its geographic-economic base to a point from which it could use the natural and human resources of all Italy as a nucleus upon which to build the Roman Empire in Europe, West Asia and North Africa.