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)

First graders attend a festive ceremony to mark the start of another school year in Slaviansk, September 1, 2014. September 1 marks the start of a new academic year for students in Ukraine. (Photo by Gleb Garanich/Reuters)

Model Juliana Paesthe (C) of Viradouro samba school participates in the annual carnival parade in Rio de Janeiro's Sambadrome, February 15, 2015. (Photo by Ricardo Moraes/Reuters)

Keira Knightley attends the premiere for “A Dangerous Method” at The 55th BFI London Film Festival at The Odeon West End on October 24, 2011 in London, United Kingdom. (Photo by Dave Hogan/Getty Images)

Two Bunny Girls from the Playboy Club and two Penthouse Pets from the Penthouse Club prepare to take part in the annual Good Friday waiters and waitresses race in Battersea Festival Gardens, London, 28th March 1972. (Photo by Ian Showell/Keystone/Hulton Archive/Getty Images)

Demonstrators wear skull masks during an anti government protest, as Chile's President Michelle Bachelet delivers a speech inside the National Congress, in Valparaiso city, Chile May 21, 2016. (Photo by Ivan Alvarado/Reuters)