Human civilizations have been scientifically and culturally interconnected in societies through the centuries. When a nation gains prosperity, other nations make that prosperity their own. This human instinct of solidarity and inter-dependence, if not well directed and controlled, turns out to be a kind of public charge. This means that some feel satisfied with taking from what others have achieved. Right from the beginning of life on earth, civilizations existed.
Every century presents a different kind of civilization which disappears as the century ends.
They come and go leaving behind totally unproductive societies. The new generation have given up creativity, and are contented with their ancestors' accomplishments. From this comes the necessity of searching history. Yemen's civilization did not vanish with the destruction of Mareb Dam. It was alive inside every Yemeni, though they happened to be ignorant people and wandering nomads.