So if it's really been 15,000 years, how come the city still looks almost completely normal, just with some moderate technological improvements? 15,000 years, especially at the rate we're going by, would be more than enough for humanity to reach the technological singularity and make most contemporary designs for [i]everything[/i] entirely obsolete. Has society gone through [i]multiple[/i] gigantic wars that sent everyone back to the stone age?