I remember very vividly, as a child growing up in England, living through the Cuban Missile Crisis. For a few days, the entire biosphere seemed to be on the verge of destruction. And the same weapons are still here, and they're still armed. If we avoid that trap, others are waiting for us.

I believe human beings mark a threshold in the development of the planet, of course, but it is only part of the picture. What Big History can do is show us the nature of our complexity and fragility and the dangers that face us, but it can also show us our power, with collective learning.

Learning to domesticate the horse was a sort of energy revolution.

Unfortunately, historians have become so absorbed in detailed research that they have tended to neglect the job of building larger-scale maps of the past.