Sugar gliders, Candy and Popcorn, enjoy their favourite food, Nectar, at Wild Life Sydney Zoo on February 14, 2017 in Sydney, Australia. The treat made up of honey, high protein baby cereal and egg yolks is the human equivalent to chocolate to the Sugar Gliders. St. Valentine's Day or the Feast of Saint Valentine began as a celebration of the early Christian Saint Valentinus. From the 18th Century onwards it has steadily transformed into a celebration of romantic love and sentiment in many countries around the world. (Photo by James D. Morgan/Getty Images)

Afghan dogs fight during the weekly dog fight in Kabul, Afghanistan, 17 February 2017. Under the Taliban dog fighting was forbidden, but since their fall it has become a major source of entertainment for hundreds of Afghans, where bets can amount to thousands of dollars and the dogs, which must be over one year old, are well-cared for by their owners and fed milk, butter and meat. (Photo by Hedayatullah Amid/EPA)

Shot by Bert Hardy, the black and white images show prisoners carrying out remedial tasks such as untying knots in post office string and sewing mail bags. Other intriguing shots show lags doing their daily one hour outdoor exercise, being frisked for contraband items by officers during a routine “rub down” and serving evening meals. Strangeways was designed by Alfred Waterhouse and cost £170,000 ($207,910) to build. The prison, famed for its prominent ventilation tower and imposing design, has become a local landmark. Here: A prison officer frisking prisoners during the “rub-down” at Strangeways Prison in Manchester, UK on November 1948. (Photo by Bert Hardy/Picture Post/Hulton Archive/Getty Images)

5-year-old Chinese girl Wang Anna prepares meals for her grandmother and great-grandmother at home in Zhuyuan village, Guizhou province, China on March 3, 2017. Chinese girl called Wang Anna, 5, takes care of her ill grandmother and 92-year-old great-grandmother on her own every day in a mountainous village in Zhima town, Zunyi city, southwest China's Guizhou province. Her father went to jail before she was born and her mother remarried after gave birth to her. Although she is just five years old, she started to shoulder the responsibility to look after ill grandmother and elderly great-grandmother. (Photo by Imaginechina/Rex Features/Shutterstock)

Aliia Nasyrova laying her hair on the couch to show her hair's length on March 5, 2017 in Riga, Latvia. Real-life Rapunzel Aliia Nasyrova has hair so long that her husband admits he thinks of it as another member of the family. Aliia, 27, who lives in Riga, Latvia, took 20 years to grow out her hair, which measures 90 inches to the floor – and even has its own space in the marital bed. And while her massive mane attracts stares when out in public, her husband Ivan Balaban says he loves it and is proud of her for not cutting it. Weighing in at 4.5lbs (2kg), Aliia says her lengthy locks weigh as much as the family cat. (Photo by Eduard Kolik/Barcroft Media)

Respect, Kronotsky nature reserve, Russia. The photographer’s cat, Ryska – her name means little lynx in Russian – stands outside their cabin and with aggressive posturing warns off a fox. In winter, foxes would regularly visit the cabin searching for food. If one peered in at the window, possible when the snow was deep, Ryska would sit on the other side, fur raised, and growl. When outside, she would hold her ground. The foxes were not always frightened and so encounters could be a sort of dance. (Photo by Igor Shpilenok/Unforgettable Behaviour/NHM)

Przemek Pawlicki performs during training in Leszno, Poland on May 12, 2016. A stunning action-packed catalogue of photographs from sporting events around the world has been released by Red Bull. The energy drink giant's photographers have been busy capturing extraordinary images of action sports and some of the world's greatest daredevils. (Photo by Lukasz Nazdraczew/Red Bull/SWNS.com)

Kung Fu master Li Liangui practices “Suogugong” Kung Fu and his wife Liang Xiaoyan (R) practices Qigong at a park in Beijing, China, June 30, 2016. For 50 years, kung fu master Li Liangui has been contorting his body into eye-watering positions while practising one of the more unusual and less popular Chinese martial art forms. The 70-year-old is an expert in suogugong, or body shrinking kung fu, where practitioners dislocate their bones to help them achieve unlikely positions and feats. (Photo by Kim Kyung-Hoon/Reuters)