the only exception to this universal ignorance of the arabian peninsula concerns yaman and the coastline of the persian gulf and arabian sea. this exception is not due merely to their near location to the sea and ocean but to their radical difference from the rest of the arabian peninsula. rather than being a barren desert profitless to befriend, explore, or colonize, these lands were fertile and had well-defined seasons with a fair amount of rainfall. they had an established civilization with many urban centers and long-lasting temples. its people, the banu himyar, were well endowed and intelligent. they were clever enough to think of ways of saving rain water from running down to the sea and of making good use of it. they built the dam of ma'rib and thereby changed the course which water would have naturally followed to courses such as settled life and intensive agriculture required. falling on high mountains, rain water would gather in a 400 meters wide valley flanked by two mountains east of the city of ma'rib. it would then divide into many streams and spread over a wide plain that is very much like the nile in the dam area in upper egypt. as their technological and administrative skill developed, the people of yaman constructed a dam at the narrowest point between the two mountains with gates which allowed controlled distribution of water. by putting the resources of their country to good use, they increased the fertility of the land and the prosperity of the people. what has so far been discovered-and is still being discovered-by way of remains of this himyari civilization in yaman, proves that it had reached an impressive height and was strong enough to withstand not only a number of great political storms but even war.