COVER: © Ingrid Visser / ​ SeaPics.com; page 2: Australia: Photo by Jonathan Wood / ​ Getty Images; Tuvalu: Gary Braasch / ​ ZUMA Press
COVER: © Ingrid Visser / ​ SeaPics.com; page 2: Australia: Photo by Jonathan Wood / ​ Getty Images; Tuvalu: Gary Braasch / ​ ZUMA Press