From Helmut Krueger, Haar, Germany
Now we have realised that we messed up Earth by changing the climate and overpopulating the planet, we cling to the thought that we have left some traces that will tell future alien visitors or intelligent cockroaches about us: we created the Anthropocene, even if it is just radioactive waste, microplastics and rocks formed from garbage(19 July, p 24). What a legacy!
