An aerial view shows people touring between the large-scale ice sculptures at the 18th Harbin Ice and Snow World during its trial run opening to public in Harbin city, Heilongjiang province, China, 21 December 2016. Some 180,000 cubic meters of ice and 150,000 cubic meters of snow were used to build the 800,000-square-meter ice wonderland. The 33rd Harbin International Ice and Snow Festival will kick off on 05 January 2017 that will last about three months. (Photo by Tian Weitao/EPA)

Andrea Petkovic of Germany in action against Sara Errani of Italy during day one of the Mutua Madrid Open tennis tournament at the Caja Magica on May 3, 2014 in Madrid, Spain. (Photo by Julian Finney/Getty Images)

Wedges of an orange generate enough current and electrical juice – 3.5 volts – to power an LED. The fruit’s citric acid helps electrons flow from galvanized nails to copper wire in this 14-hour exposure. This image was published in September’s Visions of Earth, a trio of photos that appear in each issue of National Geographic. (Photo by Caleb Charland/National Geographic)

An AI Gamer “Q56” robot plays a video game during a demonstration at the Bandai Namco Holdings Inc. booth at the Combined Exhibition of Advanced Technologies in Chiba, Japan on October 16, 2019. (Photo by Kiyoshi Ota/Bloomberg)

Naki'o, a mixed-breed dog with four prosthetic devices, goes for a run in Colorado Springs April 12, 2013. Naki'o lost all four feet to frostbite when he was abandoned as a puppy in a foreclosed home. (Photo by Rick Wilking/Reuters)

“Lobsang and 66 fellow monks were imprisoned in 1959. When released 21 years later, he was one of only three survivors. While in prison his best friend, a rinpoche, died in his arms. Tensin was later discovered to be the reincarnation of that friend. Lobsang said there are so many characteristics of his old friend in the young boy”. (Photo and caption by Phil Borges)

Xiren Wang, Lili Wat, and Sitong Chen join the pageant’s opening routine, dancing to “The Boys”, a song by K-Pop group «Girls’ Generation». While the women come from a range of professional backgrounds – including economics, nursing, and acting – every contestant is looking for her big break into the entertainment industry. Most contestants said they would prefer to have a career in the U.S. but would go wherever the opportunity lies. (Photo and caption by John Brecher/Sahra Vang Nguyen/NBC News)

“YagYang”. The Apatani are tribal people living in north east of India in the region of Arunachal Pradesh. Tattooing and stuffing of large nose plugs is the particularity of these women. YagYang 75 years old, her husband passed away few months ago and she feels very alone, during my visit I was very fond of this woman and I wanted to spend some more time with her, so I asked her which was her favorite dish. The next day i returned with the fresh fish, as she mentioned, and when she saw me she was very happy and welcomed me with a big smile. Photo location: India. (Photo and caption by Passarini Mattia/National Geographic Photo Contest)