During their tour of Australia, New Zealand, Fiji and Tonga last year, Harry and Meghan unveiled six dedications to the Canopy and welcomed commitment to the initiative by its latest member, Kiribati.

"Planting trees and conserving forests helps us in so many ways," Harry said during the tour. "It is a simple, but effective way to restore and repair our environment."

Darwin's five-year voyage around the world in the 1830s gave the young naturalist valuable insight into the natural world and helped influence his thinking as he prepared his ground-breaking work "On the Origen of Species."

Reuters