We are the descedent's of the oldest civilization.

It is believed and extensively studied and reported that the civilization in Harrappan days - dates back to 6000BC; was eloquently planned and executed. The cities had extensive and simple planning. They never had any kind of technology to support their plans nor they had the resources we have today.
But why ? echo it again ' But why ?' . We being the descendent's from the great civilization have such a horrific planned city. Is it we have been genetically modified ?
Are u ?