Contents

27 May 2016
Vol 352, Issue 6289

About The Cover

Cover image expansion

COVER Clouds surrounding the Sphinx Observatory, which is part of the high-altitude research station Jungfraujoch (3580 meters above sea level) in the middle of the Swiss Alps, a stone's throw from the Eiger north face. This location is ideal for hunting the tiny particles upon which cloud droplets grow, as well as for studying how these particles are formed at high altitude. See page 1109.
Photo: Jonathan Reid