‘PEN GUINS ARE
IMPORTANT
SENTINELS
FOR THE WIDER
HEALTH OF
THE OCEANS.
SHIFTS IN
PENGUIN
POPULATIONS
IN THE
WATERS OFF
ANTARCTICA—
THE SOUTHERN
OCEAN—ARE
WARNING SIGNS
THAT THE
ECOSYSTEM
IS BEING
DISRUPTED.’100
NATIONAL GEOGRAPHIC NOVEMBER 2021
Archaeology: 100
World Wonders ..........P. 4 0
Crisis in Ethiopia ..........P. 8 2
An Icy Realm in Peril ..P. 100
A Journey’s Lessons ....P. 122FEATURES
PHOTO: THOMAS P. PESCHAK