A reveller walks through the streets in the early hours during traditional May Day celebrations in Oxford, Britain, May 1, 2015. (Photo by Dylan Martinez/Reuters)

Labourers work at the installation site of Liquefied Petroleum Gas (LPG) pipeline on May Day or Labour Day in Chandigarh, India, May 1, 2015. (Photo by Ajay Verma/Reuters)

Brandy Shelton of Greensboro, North Carolina, “twerks” for a group of bikers on Ocean Boulevard during the 2015 Atlantic Beach Memorial Day BikeFest in Myrtle Beach, South Carolina May 22, 2015. After three people were killed and seven wounded in shootings during 2014 Bikefest, State officials called for an end to the event that draws thousands to the family-friendly beach town.Their efforts were unsuccessful. Bikers returned to Myrtle Beach – just a week after a bloody motorcycle gang shootout in Waco, Texas. But this time authorities are more prepared, with dozens of new surveillance cameras and a police force three times the size of last year's. (Photo by Randall Hill/Reuters)

This photo taken on December 2, 2015 shows a lenticular cloud forming as white streaks from airplanes mark the blue sky, in a rare atmospheric phenomena above the town of Gevgelija on December 2, 2015. Lenticular clouds have been regularly confused for UFOs throughout history due to the their smooth, round or oval lens-shaped structure. (Photo by Armend Nimani/AFP Photo)

Relatives and friends react during the funeral of Bryan Sandoval, 17, a victim of a landslide that has left at least 112 dead and 350 missing people, in El Cambray II village, Santa Catarina Pinula, Guatemala, 04 October 2015. The landslide took place on 01 October 2015 when heavy rains saturated the soil. (Photo by Esteban Biba/EPA)

Policemen take pictures of the Soyuz TMA-17M spacecraft while it is transported from an assembling hangar to its launch pad at the Baikonur cosmodrome, Kazakhstan, July 20, 2015. The Soyuz is scheduled to blast off with Kjell Lindgren of the U.S., Kimiya Yui of Japan and Oleg Kononenko of Russia to the International Space Station on July 23, 2015. (Photo by Shamil Zhumatov/Reuters)

Spanish matador Juan Jose Padilla looks at a bull during a bullfight at The Maestranza bullring in the Andalusian capital of Seville, southern Spain April 25, 2015. (Photo by Marcelo del Pozo/Reuters)

A girl walks past a destroyed mosque in the town of Mararaba, after the Nigerian military recaptured it from Boko Haram, in Adamawa state May 10, 2015. (Photo by Akintunde Akinleye/Reuters)