Historically, most Empires created by man have risen and fallen during a period of around 500 years.
By 2016 AD the great and so called democratic Western Empire, which began with the Age of Discovery during the 15th c.
However, Mankind would never become extinct as new societies inevitably replace existing social structures sooner or later.
The Romans, Greeks, Egyptians, the Moors and the Ottomans all, in their turn, reigned supreme until apathy, arrogance and, laziness led to their downfall.
Historically, most Empires created by man have risen and fallen during a period of around 500 years