A boy holds his mother's leg as he cries in front of their damaged house after a strong 6.6 magnitude earthquake at Longmen village, Lushan county in Ya'an, Sichuan province. (Photo by Jason Lee/Reuters)

“Cassowaries are large, flightless birds related to emus and (more distantly) to ostriches, rheas, and kiwis”, writes Olivia Judson in the September issue of National Geographic magazine. How large? People-size: Adult males stand well over five foot five and top 110 pounds. Females are even taller, and can weigh more than 160 pounds. Dangerous when roused, they’re shy and peaceable when left alone. But even birds this big and tough are prey to habitat loss. The dense New Guinea and Australia rain forests where they live have dwindled. Today cassowaries might number 1,500 to 2,000. And because they help shape those same forests – by moving seeds from one place to another – “if they vanish”, Judson writes, “the structure of the forest would gradually change” too. (Photo by Christian Ziegler/National Geographic)

People take part in the Classic Ride Rally in downtown Valencia, eastern Spain, 23 November 2014. Some hundred people on classic bikes from the 20's to the 70's participated in the rally. (Photo by Kai Foersterling/EPA)

A driver steers a lorry laden with bags of plastic bottles across a recycling yard at the outskirts of Beijing, China, August 19, 2016. As authorities try to control Beijing's burgeoning population and capitalize on skyrocketing land prices, scrap collectors say they are being pushed out despite playing a vital role in China's unique recycling ecosystem. (Photo by Thomas Peter/Reuters)

A narrow strip of clouds illuminated in the light of sunset before approaching rain clouds over an alley near Sieversdorf district Oder-Spree, Brandenburg, Germany on July 14, 2016. (Photo by Patrick Pleul/DPA)

A man dressed as a traditional character in the “Baile de Negras” dance poses for a picture on the feast day of the Virgin of the Candelaria (Candlemas) in the town of Diriomo, some 45 km from Managua, Nicaragua on February 2, 2017 Candlemas falls forty days after Christmas and is celebrated by Catholics as the presentation of Christ at the Temple. (Photo by Inti Ocon/AFP Photo)

A man carries schoolchildren on his bicycle on a road in Srinagar, March 28, 2017. (Photo by Danish Ismail/Reuters)

A stewardess holding a lightsabre poses for photos with visitors during a tour of the Star Wars themed All Nippon Airways ANA R2D2 Boeing 787 Dreamliner aircraft at Singapore's Changi Airport November 12, 2015. The aircraft was opened to the media on Thursday as it makes its first Asian stop outside Japan. (Photo by Edgar Su/Reuters)