Pakistani youths cool off in a stream during hot weather on the outskirts of Islamabad on April 29, 2016. Pakistan's Meteorological Department has forecast hot and dry weather in most parts of the country with the highest temperatures recorded at 41 celsius in the southern Sindh province. (Photo by Aamir Qureshi/AFP Photo)

In this May 31, 2016 photo, pieces of watermelon litter the trash area of the Coche public market in Caracas, Venezuela. Staples such as corn flour and cooking oil are subsidized, costing pennies at the strongest of two official exchange rates. But fruit and vegetables have become an unaffordable luxury for many Venezuelan families. (Photo by Fernando Llano/AP Photo)

New autopilot features are demonstrated in a Tesla Model S during a Tesla event in Palo Alto, California, 2015. Federal officials say the driver of a Tesla S sports car using the vehicle’s “autopilot” automated driving system has been killed in a collision with a truck, the first U.S. self-driving car fatality. The National Highway Traffic Safety Administration said preliminary reports indicate the crash occurred when a tractor-trailer made a left turn in front of the Tesla at a highway intersection. Joshua D. Brown, of Canton, Ohio, died in the accident May 7 in Williston, Florida, when his car's cameras failed to distinguish the white side of a turning tractor-trailer from a brightly lit sky and didn't automatically activate its brakes, according to government records obtained Thursday. (Photo by Beck Diefenbach/Reuters)

The Dora the Explorer balloon moves through Times Square during the Macy's Thanksgiving Day parade Thursday, November 23, 2006 in New York. (Photo by Frank Franklin II/AP Photo)

A man drinks at a "colored" water cooler in a streetcar terminal in Oklahoma City, July 1939. (Photo by Reuters/Library of Congress)

People wash in water from a broken water pipeline on the outskirts of Kolkata, India, March 30, 2016. (Photo by Rupak De Chowdhuri/Reuters)

A child sleeps under a table at the Jorkpan market in Sinkor district in Monrovia, Liberia on May 2, 2016. (Photo by Marco Longari/AFP Photo)

An enterprising Chinese man pulls a bicycle cart packed high with bags of recyclable plastic containers in Shanghai July 25, 2002. The man sells each kilogram (2.2 pounds) of plastic for 0.08 yuan ($.01) to a nearby depot. (Photo by Claro Cortes IV/Reuters)