The document discusses how geometric correlations between layers in multiplex networks can mitigate their vulnerability to targeted attacks. It finds that while degree correlations provide some robustness to random failures, they do not prevent catastrophic cascades under targeted attacks. However, geometric or similarity correlations, which place similar nodes close together in an underlying metric space representing each layer, can significantly increase robustness to targeted attacks. This effect is demonstrated through a model incorporating such correlations, as well as analyses of real-world multiplex networks that exhibit stronger geometric correlations.