Perhaps even more valuable is what at first glance seems to be a byproduct of the monolithic hive city's design. The population of any given world approximately doubles every 100 years. With each hive housing between 10 to 100 billion people and 5 to 20 hives per planet, the sheer number of Imperial citizens on a Hive World is staggering. And each of those citizens is a potential soldier for the Emperor's already uncountably vast armies. Hives manufacture far more than mere steel and silica; they are vast factories for the most useful possible resource, people. Almost every recruit into the Imperial Guard from a Hive World will already know how to handle a weapon. Hive Worlds also serve to populate newly discovered planets. Imperial citizens are gathered from various Hive Worlds (willingly