Men cover their heads from the sun while riding on a motorcycle during a hot day in Cairo, Egypt, August 17, 2015. A heatwave killed at least 61 people across Egypt from Sunday to Tuesday and caused nearly 600 people to be admitted to hospital, Egypt's health ministry said on state news agency MENA on Wednesday. (Photo by Amr Abdallah Dalsh/Reuters)

This photo provided by Joan Marcus on August 28, 2015 shows ballerina Misty Copeland in the musical “On the Town” at the Lyric Theatre in New York. Until September 6, 2015 Copeland will play Miss Turnstiles, a love interest for one of three sailors enjoying a few hours of shore leave in 1940s New York. (Photo by Joan Marcus via AP Photo)

Ukrainians wearing traditional costumes sing Kolyadky or Ukrainian Christmas Carols, as a part of Orthodox Christmas in Kiev, Ukraine, Thursday, January 7 2016. Orthodox Christians mark their traditional Christmas Day Jan. 7, with many ancient symbolic events. (Photo by Sergei Chuzavkov/AP Photo)

A woman takes a selfie picture as Turkish Kurds gather as part of Newroz celebrations in Diyarbakir, on March 21, 2016. Nowruz, the Farsi-language word for “New Year”, is an ancient Persian festival, celebrated on the first day of spring, on March 21, in Central Asian republics, Iraq, Turkey, Afghanistan and Iran. (Photo by Ilyas Akengin/AFP Photo)

Brazilian top model Gisele Bundchen poses before a fashion show by German designer Karl Lagerfeld as part of his latest inter-seasonal Cruise collection for fashion house Chanel at the Paseo del Prado street in Havana, Cuba, May 3, 2016. (Photo by Alexandre Meneghini/Reuters)

Victoria's Secret Angel Martha Hunt celebrates the 2015 What Is s*xy? List in San Diego on September 26, 2015 in San Diego, California. (Photo by Joe Scarnici/Getty Images for Victoria's Secret)

Children play football in front of an abandoned train compartment next to a railway track in Dhaka, in this May 29, 2014 file photo. (Photo by Andrew Biraj/Reuters)

China's Shang Chunsong prepares to compete in the uneven bars event of the women's individual all-around final artistic gymnastics competition at the Namdong Gymnasium Club during the 17th Asian Games in Incheon, in this September 23, 2014 file photo. (Photo by Kim Hong-Ji/Reuters)