For more than 2,000 years, women from the Baiga tribe in the highland district of Dindori, in central India’s Madhya Pradesh state, have been tattooed. Sumintra, 25, from Bona village, has the markings across her forehead, legs and arms. The women who work as tattoo artists are knowledgable about the different types of designs and pigments preferred by various tribes, and their meanings are passed to them by their mothers. The tattooing ‘season’ begins with the approach of winter. (Photo by Ronny Sen/WaterAid/The Guardian)

A pigeon, known as Siyah Kinifirli, with an approximate market value of 1000 Turkish Lira ($263), bred by 23-year-old Ismail Ozbek, is pictured in Sanliurfa, Turkey, December 23, 2016. As night-time approaches in Sanliurfa, southeastern Turkey, most of the alleyways of the city's old bazaar are emptying out of buyers and vendors, except for one. (Photo by Umit Bektas/Reuters)

Female female male threesome. My bit on the side is my best male friend. (Photo by Laoshi/Getty Images)

With its huge eyes, comical name and diminutive size, Mark R. Smith’s image of a baby Hawaiian bobtail squid can’t help but raise a smile. A curiously endearing creature, the cephalopod is just 1.5cm across, its mantle cavity bearing more than a passing resemblance to a rather natty shower cap. But it is also a beautiful example of symbiosis – nature’s version of “I’ll scratch your back if you scratch mine” – for on the underside of the squid is a light organ which houses bioluminescent bacteria. The squid offers the bacteria protection and food, while the bacteria emit a glow – a handy trait that the squid uses to offset its silhouette, helping it to evade predators in the depths below. Mark R. Smith’s entry combines several images of a Hawaiian bobtail squid with different focus lengths to create a final picture with greater depth of field than normal. (Photo by Mark R. Smith/Wellcome Images/Macroscopic Solutions)

A young woman wearing no trousers hits the ski slopes at a ski resort in Xuzhou, in east China's Jiangsu province on January 13, 2015 in a promotional effort to equal “No Pants Subway Ride”, which was marked on January 11 this year. The promotional “No Pants Subway Ride” stunt on January 11 was held as commuters in some 60 cities around the world braved public transportation in their undies, which has gone global since its first staging by US group Improv Everywhere in New York in 2002. (Photo by AFP Photo)

From house breaking in Johannesburg to hippos on the loose in Tbilisi to rioters attacking a policewoman in Burundi, Reuters photographers tell the story behind some of the most iconic pictures of the year. Here: Protesters drag a female police officer accused of shooting a protester in the Buterere neighbourhood of Bujumbura, Burundi, May 12, 2015. Goran Tomasevic: Protesters started throwing stones at a group of police, who then started to run away. The policewoman in the photo, Medikintos Inabeza, 33, got left behind and then some protesters started to push her, saying that she had shot a female protestor in the stomach with an AK47 rifle. I didn't see anything of that. There were 5 or 10 protesters pushing the policewoman at first, then others came and joined in. Up to 20 or 30 protesters were surrounding her at one point. The protesters kicked and beat her very badly; I also saw a couple of knives. I thought they were going to kill her... (Photo by Goran Tomasevic/Reuters)

Leon Feingold, right, drops his jeans as his girlfriend Patrizia Calvio looks in her purse on the uptown E Train during the 18th annual No Pants Subway Ride, January 13, 2019, in New York. (Photo by Kathy Willens/AP Photo)