The Mercedes-Benz F015 Luxury in Motion autonomous concept car is shown on stage during the 2015 International Consumer Electronics Show (CES) in Las Vegas, Nevada January 5, 2015. (Photo by Steve Marcus/Reuters)

A Pakistani farmer guides his bulls as he competes in a traditional bull race in Khunda village in the northwestern district of Attock, some 80 kilometers from Islamabad on January 3, 2015. Tens of thousands of people gather whenever there is a bull race held in Pakistan which are usually the highlight of festivals organized in rural areas of the Asian country, and attract lots of spectators due to their thrilling nature. The traditional competition attracts landlords and farmers from all around the province where the race is held, and they all bring their fastest and strongest bulls in hopes of gaining a reputation. (Photo by Aamir Qureshi/AFP Photo)

A man dressed in a condom costume walks at Caleta Portales beach, during a summer awareness campaign by the Chilean Corporation for the Prevention of AIDS in Valparaiso city, northwest of Santiago January 9, 2015. (Photo by Rodrigo Garrido/Reuters)

In this photo taken on Monday, January 5, 2015, a mallard duck attempts to walk on a frozen pond in Yukon, Okla. (Photo by Steve Gooch/AP Photo/The Oklahoman)

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)

American Yoga teacher Dashama poses on a Yoga-board during a preview of the 46th International Boat Fair in Duesseldorf January 16, 2015. The BOOT 2015 watersports fair, with more than 1,600 international exhibitors will run in Duesseldorf from January 17 to January 25. (Photo by Ina Fassbender/Reuters)

An elephant “kisses” a visitor during a show at an elephant training school in Xishuangbanna, Yunnan province, April 18, 2015. Some 16 elephants live at the school and give four 30-minute performances everyday for visitors. (Photo by Wong Campion/Reuters)

People dance Tuesday, April 28, 2015, in Baltimore. Maryland's governor vowed there would be no repeat of the looting, arson and vandalism that erupted Monday in some of the city's poorest neighborhoods. (Photo by Matt Rourke/AP Photo)