“NASA's Pathfinder, Pathfinder Plus, Centurion and Helios Prototype were an evolutionary series of solar- and fuel-cell-system-powered unmanned aerial vehicles. AeroVironment, Inc. developed the vehicles under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. They were built to develop the technologies that would allow long-term, high-altitude aircraft to serve as “atmospheric satellites”, to perform atmospheric research tasks as well as serve as communications platforms”. – Wikipedia

Photo: The solar-electric Helios Prototype flying wing is flies over the Hawaiian islands of Niihau and Lehua during the first solar-powered test flight July 14, 2001 from the U.S. Navy's Pacific Missile Range Facility on Kauai, HI. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later in the summer. (Photo Courtesy of NASA/Getty Images)

“Nomascus is the second most speciose genus of gibbons (family Hylobatidae). Originally this genus was a subgenus of Hylobates, and all individuals were considered one species, Hylobates concolor. Species within Nomascus are characterized by 52 chromosomes. Some species are all black, some light with a distinct black tuft of crown fur, and some by distinct, light-colored cheek patches. Nomascus is found from southern China (Yunnan) to southern Vietnam, and also on Hainan Island. One of the genus' species, Nomascus nasutus, has been deemed “the most critically endangered ape species in the world”. All of the species in this genus are endangered or critically endangered”. – Wikipedia

Photo: A newborn White-Cheeked Gibbon clings to its mother in the Nanning Zoo on April 12, 2004 in Nanning, Guangxi province, China. The White-Cheeked Gibbon's natural habitat is Southern China as well as Vietnam and Laos. They are classified as highly endangered and are on the brink of extinction due to poaching and reduction of natural rainforests. (Photo by Getty Images)

Matador Marco Espinola, who emigrated from the Azores two years ago, challenges a bull during an Azorean “tourada a corda” (bullfight by rope) in Brampton, Ontario August 15, 2015. Bulls in a tourada a corda are held by a rope controlled by a team of men to make sure the animal does not cause injury. Bulls are never killed, in contrast with bullfighting in Spain. The Portuguese population in Canada, numbering 429,000 in the 2011 census, mainly centers around Toronto with immigrants from the nine islands of the mid-Atlantic Azores archipelago. (Photo by Chris Helgren/Reuters)

A gory fight to the death between snarling dogs and captured wild boars. Gathered around a bamboo-walled arena, Indonesians in this remote part of Java island seem eager to watch the blood-curdling contests, known locally as “adu bagong” (boar fighting). Not surprisingly, animal rights activists are up in arms against the regular spectacle, which began in the 1960s when wild pig numbers in this area in West Java soared and they were hunted to protect crops. Here: Women share a joke as they walk to a paddy field in Cikawao village of Majalaya, West Java province, Indonesia, October 12, 2017. (Photo by Reuters/Beawiharta)

In this July 5, 2016 photo, a tamed elephant rests in a pool of water by a road in Baduraliya, a village outside Colombo, Sri Lanka. Even as the country cracks down on illegal ownership, the enduring demand for elephants has the government planning to set up its own pool of captive animals to be hired out to temples for ceremonies and maintained with budget funds. (Photo by Eranga Jayawardena/AP Photo)

Indonesian mahouts clean their Sumatran elephant in a river near the zoo in Medan, North Sumatra, Indonesia, 12 December 2014. According media reports, the smallest of the Asian elephants, Sumatran elephant (Elephas maximus sumatrensis) is facing serious pressures arising from illegal logging and associated habitat loss and fragmentation in Indonesia. The population has come under increasing threat from rapid forest conversion to plantations. (Photo by Dedi Sahputra/EPA)

Hundreds of Nigerians celebrate at an intersection in the flashpoint northern city of Kaduna on March 31, 2015 the victory of main opposition All Progressives Congress (APC) presidential candidate Mohammadu Buhari. (Photo by Nichole Sobecki/AFP Photo)