In this October 15, 2014 file photo, Katsu Nakamura, sky division manager for Yamaha USA, moves the RMax unmanned helicopter into position before a demonstration of its aerial application capabilities at the University of California, Davis' Oakville Station test vineyard in Oakville, Calif. Researchers at UC Davis have been studying the effectiveness of the drone's ability for spraying pest control and nutritional materials on the test vineyard in California's Napa Valley. (Photo by Rich Pedroncelli/AP Photo)

A man holds up for a picture a one hundred trillion Zimbabwean dollars note inside a shop in Harare, Zimbawe, June 12, 2015. Hyperinflation in Zimbabwe was a period of currency instability that began in the late 1990s shortly after the confiscation of private farms from landowners, towards the end of Zimbabwean involvement in the Second Congo War. During the height of inflation from 2008 to 2009, it was difficult to measure Zimbabwe's hyperinflation because the government of Zimbabwe stopped filing official inflation statistics. However, Zimbabwe's peak month of inflation is estimated at 79.6 billion percent in mid-November 2008. (Photo by Philimon Bulawayo/Reuters)

Looking for love by Tony Wu, USA. Highly commended, Animal Portraits. “Accentuating his mature appearance with pastel colours, protruding lips and an outstanding pink forehead, this Asian sheepshead wrasse sets out to impress females and see off rivals, which he will head-butt and bite, near Japan’s remote Sado Island. Individuals start out as females, and when they reach a certain age and size – up to a metre (more than 3 feet) long – can transform into males. Long-lived and slow-growing, the species is intrinsically vulnerable to overfishing”. (Photo by Tony Wu/2018 Wildlife Photographer of the Year)

A Romanian honor guard soldier stands still as three military aircraft carriers are crossing the sky during a ceremony held at the Unknown Soldier Memorial, in Carol I Park, on the occasion of the Heroes' Day commemoration, in Bucharest, Romania, 10 June 2021. (Photo by Robert Ghement/EPA/EFE)

Revellers perform during the “Salsodromo”, the kick-off of the music and cultural festival Feria de Cali (Cali Fair) in Cali, Colombia, on December 25, 2021. The “Salsodromo”, an event in which more than 2,500 revellers and salsa music dancers perform along a kilometre-long stripe, marks the start of the Feria de Cali festival every year. (Photo by Paola Mafla/AFP Photo)

A tourist watches as the moon passing in front of the sun as it approaches a full solar eclipse in the northern Australian city of Cairns November 14, 2012. (Photo by Tim Wimborne/Reuters)

A Republican farmer defending a farm on the outskirts of Irun against Nationalist forces during the Spanish Civil War, 6th September 1936. A comrade lies dead by his side. (Photo by Keystone/Hulton Archive/Getty Images)

Merit: A Night at Deadvlei. The night before returning to Windhoek, we spent several hours at Deadveli. The moon was bright enough to illuminate the sand dunes in the distance, but the skies were still dark enough to clearly see the milky way and magellanic clouds. Deadveli means “dead marsh. The camelthorn trees are believed to be about 900 years old, but have not decomposed because the environment is so dry. (Photo and caption by Beth McCarley/National Geographic Traveler Photo Contest)