Aerobatic pilot Sean D. Tucker flies in the two-seat Oracle Extra airplane over downtown Chicago skyline, Wednesday, June 8, 2016. Tucker will perform before the start of of the America's Cup World Series racing on Saturday and Sunday. (Photo by Kiichiro Sato/AP Photo)

A sales assistant poses for photographs with a mealworm cookie in Seoul, South Korea, August 8, 2016. Insect-eating, or entomophagy, has long been common in much of the world, including South Korea, where boiled silky worm pupae, or beondegi, are a popular snack. Now, South Korea is looking to expand its insect industry as a source of agricultural income. (Photo by Kim Hong-Ji/Reuters)

An armed man herds his cattle close to the village of Nimini in northern South Sudan, February 8, 2017. In the chaos of South Sudan's civil war, it took three years for Nyagonga Machul to find her lost children. Machul had traveled from her village to the capital when President Salva Kiir, an ethnic Dinka, fired his deputy Riek Machar, a Nuer, in 2013. (Photo by Siegfried Modola/Reuters)

Farmers clash with riot policemen during a protest outside the Greek Agriculture Ministry on March 8, 2017 in Athens, Greece. Two people were detained after the windows of two police vans were smashed as approximately 1,000 farmers, mainly from the island of Crete, took part in the protest. (Photo by Nikolas Georgiou/ZUMA Wire/Rex Features/Shutterstock)

Dancers wait at backstage as they prepare for a dance performance during the Bali Arts Festival in Bali, Indonesia, Wednesday, June 21, 2017. The resort island of Bali is holding a month-long annual Bali Arts Festival from June 10 to July 8. (Photo by Firdia Lisnawati/AP Photo)

Protesters hold on to each other as they are sprayed with water from police water cannons in Martyr square, downtown Beirut, Lebanon October 8, 2015. Lebanese security forces fired tear gas and water cannons to break up an anti-government protest in Beirut on Thursday, and the country's fractious leaders postponed talks aimed at resolving a political crisis that is feeding public discontent. (Photo by Aziz Taher/Reuters)

Skulls placed on the floor are seen during a ceremony held for the "Dia de las natitas" (Day of the Skull) celebrations at the General Cemetery of La Paz, November 8, 2015. Bolivians, who keep close relatives skulls at home as a macabre talisman, flock to the cemetery chapel once a year to have the craniums blessed and to bring themselves good luck in the future. (Photo by David Mercado/Reuters)

Employees work at a sorting centre of Zhongtong (ZTO) Express ahead of the Singles Day shopping festival, Chaoyang District, Beijing, November 8, 2015. On China's giant Singles Day internet shopping festival, the country's delivery firms are stretched so thin that they are looking for tie-ups, listings and new investors to husband their resources. (Photo by Jason Lee/Reuters)