The defining moment of the pre-historic era
was the ability of man to control fire. Many people would argue that it was
actually man’s quest for fire that distinguished it from other pre-historic
creatures, but it was our ancestor’s ability to control fire that changed the
dynamics of the world forever.
Previously, all of mankind had to rely on themselves (in little tribal structures) for protection, food and heat. Even with the discovery of fire, the tribal family still would huddle around the open fire for heat, looking out for wild animals whilst they were eating or entertaining themselves.
With the advent of the chimney, they had the ability to control fire indoors on a long-term basis. That changed the architecture of their accommodation, and the way in which they worked. Members of the tribe could wander off further from the fires looking for food, opening them up to new dangers and new opportunities. It also enabled smaller groups – and eventually individuals to survive- on their own without the heat and protection of other members of the tribe. I would guess that it was not long after this that they experienced for the first time loneliness and eventually depression.
And in the end it was the furnace at which the steel was forged that fuelled the industrial revolution. The modern high-rise block of units is a symbol of what has happened to mankind because of the invention of the humble chimney.
 Charles Handy the British management philosopher was the first to highlight this idea.