Our planet is now 4.6 billion years old. We have been walking around on it for seven million of these, but it is only in the past 6,000 years that we have formed civilisations and built big. Before this, we built simple, modest buildings with locally sourced natural materials – timber, stone, air-dried clay bricks. 

It was not until the time of the Egyptians that the power of human labour was harnessed en masse, that we scaled up and built much larger structures: the pyramids, the great stone temples, the Colosseum. We relied on the ability to feed the population to increase output but were still using low-embodied materials with little impact on the planet.