Rihanna celebrates by flashing the crowd on July 13, 2014 in Rio de Janeiro, Brazil. (Photo by Twitter.com)

Visitors attend a press preview of the 2012 Whitney Biennial at the Whitney Museum of American Art on February 27, 2012 in New York City. The contemporary art exhibition includes sculpture, photography, painting, installations, dance, theater, film and music and runs from March 1 through May 27. (Photo by Mario Tama/Getty Images)

Members of the Indonesian Presidential Security Forces (Paspampres) show their skills during the simulation of a terrorist attack in Jakarta, Indonesia, 29 December 2016. According to reports in local media the Indonesian security forces have already arrested 21 terrorists suspects and fatally shot five of them, who were allegedly planning attacks in the Indonesian capital during the Christmas and New Year's Eve celebrations this year. The presentation was shown on the occasion of a visit by Indonesian President Joko Widodo and a delegation to the Paspampres headquarters in Jakarta. (Photo by Bagus Indahono/EPA)

Sandra, a 29-year-old orangutan at Buenos Aires' zoo, on May 20, 2015. Sandra got cleared to leave a Buenos Aires zoo that was her home for 20 years, after a court ruled she was entitled to more desirable living conditions. (Photo by Juan Mabromata/AFP Photo)

"Temptation", part of an installation from the artist-duo David Burns and Austin Young, appears among the works of 30 artists in the multimedia exhibition "The Value of Food: Sustaining a Green Planet" at the Cathedral of St. John the Divine, Wednesday, October 7, 2015, in New York. The exhibition, installed in the cathedral's seven chapels and 14 bays, explores food accessibility, sustainability and other food-related issues and runs through April 3, 2016. (Photo by Bebeto Matthews/AP Photo)

Puppies, pugs and the perfect antidote to political pandemonium, it’s the Kennel Club’s dog photographer of the year competition. Here: Jamie Morgan’s two Afghan hounds won first place in the portrait category. (Photo by Jamie Morgan/PA Wire)

Aurora Australis from Beerbarrel Beach, by James Stone. Runner Up: Aurorae. (Photo by James Stone/Astronomy Photographer of the Year)

A handout photograph provided by Brian Kubicki of Costa Rican Amphibian Research Center on 26 April 2016 shows a “Crystal frog”, Hyalinobatrachium dianae (H. diane). This frog was discovered by US biologist Brian Kubicki and Costa Ricans Stanley Salazar and Robert Puschendorf in a rainy forest of Costa Rican caribbean after 40 years without notice of any new example of this kind. (Photo by Brian Kubicki/EPA/Costa Rican Amphibian Research Center)