Contents

13 September 2019
Vol 365, Issue 6458

About The Cover

Cover image expansion

COVER Runoff water rushes through the valley below El Altar, Ecuador's fifth-tallest volcano. The Ecuadorian Andes were the cradle of mountain science, pioneered by Alexander von Humboldt. Two centuries on, mountain research continues to build on Humboldt's foundations, with key relevance for human society in the era of rapid climate change. See page 1092.
Photo: Ryan Heffernan/Cavan Images