Julian, left, is photographed by his mother with friend Gianluca, right, under water at a public pool in Gelsenkirchen, Germany, on a hot Friday, July 3, 2015. Germany faces a heat wave with temperatures up to 38 degrees Celsius (100 degrees Fahrenheit) at the weekend. (Photo by Martin Meissner/AP Photo)

National police transport an anti-government protester detainee during a protest against Nicolas Maduro's government in Caracas March 13, 2014. Venezuela's state prosecutor said on Thursday the death toll from a month of violent protests had risen to 28, after the nation's top court ordered opposition mayors to dismantle barricades set up by street protesters. State prosecutor Luisa Ortega Diaz, speaking on the sidelines of the U.N. Human Rights Council in Geneva, also said 1,293 detainees had been released and 104 remained in custody accused of serious crimes during the anti-government demonstrations. (Photo by Carlos Garcia Rawlins/Reuters)

An Indian Sadhu, or Hindu holy man, sits for a community feast at the Sangam, the confluence of the Rivers Ganges, Yamuna and mythical Saraswati, during the annual month-long Magh Mela religious fair in Allahabad, India, Friday, January 16, 2015. Hundreds of thousands of devout Hindus are expected to take holy dips at the confluence during the astronomically auspicious period of over 45 days celebrated as Magh Mela. (Photo by Rajesh Kumar Singh/AP Photo)

Protesters wear masks, the left in the colors of the Kenyan national flag, as they join others carrying mock coffins and red-painted crosses, symbolizing the blood of the 28 non-Muslims singled out and killed in the recent attack on a bus in Mandera by Somali militant group al-Shabab, outside government offices in downtown Nairobi, Kenya Tuesday, November 25, 2014. (Photo by Ben Curtis/AP Photo)

Recycling artist Nicolas Gomez checks the strings of a cello he has made out of an oil barrel for the Orchestra of Recycled Instruments of Cateura, in Cateura, Paraguay February 13, 2015. Saudi Arabia's oil exports have risen in February in response to stronger demand from customers. As OPEC's top producer battles for market share Reuters photographers around the globe have been photographing oil barrels to document how they are utilised once the fuel has been used. (Photo by Jorge Adorno/Reuters)

UFC women's bantamweight champion Holly Holm and Miesha Tate face off during the UFC 196 weigh ins at the MGM Grand Garden Arena in Las Vegas on Friday, March 4, 2016. (Photo by L.E. Baskow/Las Vegas Sun via AP Photo)

A woman poses for a photographer (not pictured) as a man sits next to her in downtown Catania, Italy April 20, 2016. (Photo by Tony Gentile/Reuters)