Patients from Rady Children's Hospital hug a bottlenose dolphin after being invited to swim and interact with dolphins at Sea World in San Diego, California August 27, 2015. Sea World has hosted Dolphin Interaction Program for seven years. It was started by dolphin trainer Joy Soto who battled and overcame non-Hodgkin’s lymphoma. (Photo by Mike Blake/Reuters)

A naked Hindu holy man arrives to bath in the Godavari River during Kumbh Mela, or Pitcher Festival, at Trimbakeshwar in Nasik, India, Saturday, August 29, 2015. Hindus believe taking a dip in the waters of a holy river during the festival, will cleanse them of their sins. According to Hindu mythology, the Kumbh Mela celebrates the victory of gods over demons in a furious battle over a nectar that would give them immortality. (Photo by Rajanish Kakade/AP Photo)

Yalena Leuliette, 7, of Greenbelt, Md., throws seeds from a cattail plant up in the air as she plays while visiting the Kenilworth Aquatic Gardens in northeast Washington, on Sunday, August 9, 2015. Leuliette visits the public garden with her parents a few times a year. (Photo by Jacquelyn Martin/AP Photo)

Forrest Walker, “Police Walk”. Walker describes this shot, taken in 2015 at the last officially permitted Pride parade in Istanbul, as a tense and surreal experience. His focus is on a woman walking calmly in front of a line of riot police, her attitude part defiance and part performance. (Photo by Forrest Walker/All About Photo awards 2025 via The Guardian)

Model Olivia Culpo (L) and host Nick Jonas, after getting slimed, backstage during Nickelodeon's 28th Annual Kids' Choice Awards held at The Forum on March 28, 2015 in Inglewood, California. (Photo by Lester Cohen/KCA2015/WireImage)

The tusk of a woolly mammoth that lived some 18,000 years ago, from which researchers sequenced the extinct mammal's entire genome, is seen in northeastern Siberia in this photo from 2015. (Photo by Love Dalen/Handout via Reuters)

Cosplayers dressed as Star Wars characters Chewbacca (R) and Darth Vader talk at a Star Wars Day fan event in Tokyo May 4, 2015. Star Wars fans celebrate May 4 as Star Wars Day, a pun that comes from an iconic quote in the movie, “May the Force be with you”. (Photo by Toru Hanai/Reuters)

Artist Heather Dewey-Hagborg's 'Stranger Visions', comprising of 3D printed faces extracted from DNA taken from discarded cigarette butts and chewing gum, is displayed at the Big Bang Data exhibition at Somerset House on December 2, 2015 in London, England. The show highlights the data explosion that's radically transforming our lives. It opens on December 3, 2015 and runs until February 28, 2016 at Somerset House. (Photo by Peter Macdiarmid/Getty Images for Somerset House)