Horse racing is part of Naadam, a festival organized every July in Mongolia to celebrate the People’s Revolution. Using children as jockeys in such races has a centuries-long tradition. Boys and girls as young as 5 (although the law imposes a minimum age limit of 7) ride in races that can be dangerous, with hundreds of horses running across the steppe at distances of 12 to 28 kilometres at great speeds. (Photo by Tomasz Gudzowaty)

A Chinese girl touches the gun of a relievo featuring Chinese soldiers fighting with Japanese troops during World War II at an exhibition at the Anti-Japan War Museum to mark the 60th Anniversary of the Victory of the Chinese People's War of Resistance Against Japan on August 18, 2005 in Beijing, China. (Photo by Cancan Chu/Getty Images)

Girls look at a newly installed “Renew” media point in the City of London on January 26, 2012 in London, England. The “pods” will transmit each market day and will include breaking news, weather and travel information, and information about sport, fashion, the arts and entertainment. The stations which will also double as recycling points are run by media company Renew. (Photo by Dan Kitwood/Getty Images)

“The saguaro (scientific name Carnegiea gigantea) is a large, tree-sized cactus species in the monotypic genus Carnegiea. It is native to the Sonoran Desert in the U.S. state of Arizona, the Mexican state of Sonora, a small part of Baja California in the San Felipe Desert and an extremely small area of California, U.S. The saguaro blossom is the State Wildflower of Arizona”. – Wikipedia

Photo: Daniel Appel (L), a firefighter with Engine 84 from the Lassen National Forest in California and Mike Hallen, (R), Arizona representative of the National Register of Big Trees, measure the circumference of this Saguaro cactus called the "Grand One," in the Tonto National Forest on July 1, 2005 35 miles north of Phoenix, near Carefree, Arizona. The cactus, estimated to be more than 200 years old, measures a circumference of 7 feet, 10 inches (2.4 meters) and stands 46 feet high (14 meters). The cactus was burned in the Cave Creek Complex fire and may not survive. It was once the largest Saguaro in the world, two others have been found recently that have tied it's measurements. The fire has burned more than 214,000 acres of the Sonoran desert. (Photo by Jeff Topping/Getty Images)

Life reconstruction of the new oviraptorosaurian dinosaur species Anzu wyliei in its 66 million-year-old environment in western North America as seen in an undated handout illustration by Mark A. Klinger, Carnegie Museum of Natural History. Some 18,000 species, great and small, were discovered in 2014, adding to the 2 million already known, scientists said on May 21, 2015 as they released a “Top 10” list that highlights the diversity of life. Anzu wyliei, one of the top 10, dubbed “the chicken from hell”, is extinct. The feathered dinosaur whose partial skeletons were unearthed in the Dakotas was a contemporary of T. rex and Triceratops. (Photo by Mark A. Klingler/Reuters/Carnegie Museum of Natural History)

Nyibol Lual, 13 years old, helps her family to prepare the land for cultivation on May 31, 2017, in Panthau, Northern Bahr al Ghazal, South Sudan. The family has a small land where they cultivate sorghum. An estimated 63 per cent of the population in Northern Bahr al Ghazal is experiencing severe food insecurity, according to the latest Integrated Food Security Phase Classification (IPC) report. The situation is particularly bad in Aweil West and Aweil South counties, where the exhaustion of household food stocks and growing dependence on financially inaccessible markets have left the population facing Emergency levels of food insecurity. (Photo by Albert Gonzalez Farran/AFP Photo)

Clinging on with sticky toes, a green tree frog sits bravely on its unlikely friend – a large tree python. Curled around the branches of a small coconut tree, the snake appears relatively undisturbed by the bold passenger that has clambered onto its skin. Grown in captivity together, the pair display no signs of aggression or fear, comfortable with their encounters high up in the leafy branches. Photo enthusiast Fahmi Bhs watched in surprise as the frog slowly climbed along the scales of the metre long snake in a zoo in Jakarta, Indonesia. (Photo by Fahmi Bhs/Solent News/SIPA Press)

A waste picker unloads garbage at a waste transfer station in Bamako, Mali, August 19, 2018. In the Malian capital of Bamako, donkey carts driven by young men like 19-year-old Arouna Diabate play a vital role battling the fast-growing city's waste problem. Every morning before dawn, Diabate hitches his donkey to a cart and sets off on his rounds, going door-to-door to collect household garbage which he delivers to a local waste transfer station for a monthly salary of around $35. “I won't be picking up trash with a donkey cart for the rest of my life, but for now people appreciate us because we help clean up the homes of Bamako”, Diabate said. (Photo by Luc Gnago/Reuters)