U.S. singer Katy Perry slips on the icing of a giant cake that she had jumped onto as part of her performance at the MTV Latin America Awards in Guadalajara, in this October 16, 2008 file photo. (Photo by Daniel Aguilar/Reuters)

In this photograph taken on Thursday, November 20, 2014, bud tenders Maxwell Bradford, back left, and Emma Attolini display buds in the shape of Christmas trees that are on sale for the holiday season in a recreational marijuana shop in northwest Denver. The nascent marijuana industry in Colorado is targeting holiday shoppers with special deals much like traditional retailers offer. (Photo by David Zalubowski/AP Photo)

Nic Lamb rides a wave during the third heat of the first round of the Mavericks Invitational big wave surf contest Friday, January 24, 2014, in Half Moon Bay, Calif. (Photo by Eric Risberg/AP Photo)

The pictures were taken by photographer Jorge Farfan and reveal the spiders’ bright colours. The 33-year-old captured the jumping, wolf, and lycosa spiders in a riverside field near his home in La Coruna, Spain. (Photo by Jorge Fardels/Solent News/SIPA Press)

Natan Dvir, an Israeli photographer, focuses on the human aspects of political, social and cultural issues. For his “Coming Soon” series, Dvir says that in recent years, a kaleidoscopic net of huge billboards has enveloped the commercial hubs of New York. Seen here, a man looks at a Juicy Couture billboard while passing it on 52nd street close to 5th Avenue in New York, June 5, 2012. (Photo by Natan Dvir/Polaris)

Aviation enthusiast Patrick Wilson 8, from Wetherby looks at an Avro 504 k at “The Shuttlesworth Collection” at Old Warden on July 21, 2014 in Biggleswade, England. Of the 55,000 planes that were manufactured by the Royal Army Corps (RAC) during WWI, only around 20 remain in airworthy condition. Six of these belong to The Shuttleworth Collection at Old Warden, Bedfordshire, making it the most complete collection of original airworthy WWI aircraft in the world. Amongst the collection is the SE5a. The SE5a is a single seater fighter aircraft. It is an original biplane designed by the Royal Aircraft Factory, with its engine built by Wolseley Motors Ltd, and it was issued to 84 Squadron in November 1918. The National Archive in Kew has recently verified that the plane saw action in France with 84 Squadron the day before Armistice, November 10, 1918. (Photo by Dan Kitwood/Getty Images)

Syrian refugees sit behind barbed wire as they wait to cross into Macedonia at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

Photographer Andy Hall joins the thousands of fans from west Africa who have gathered for Baaba Maal's annual Blues du Fleuve festival in Senegal. Here: Dancers wait to perform on stage. (Photo by Andy Hall/The Observer)