14 All early civilizations, including the Indus Valley Civilization, had some unique characteristics. Thus, the IVC was the first major urban civilization with architectural, street, and drainage planning not found anywhere else in the ancient world. Its technical skills were of a very high order, and so was its metallurgical talent for making bronze as hard as steel. For all its expanse, there was hardly any security except for the citadel walls, which were in some cases a protection against high tides or floods. It was par excellence a peace-loving civilization. Nowhere among its 1,500 sites has any evidence been found of armies or caches of weapons, or a major battle or the taking of prisoners of war. (page 18)