Lightning illuminates a thundercloud as a storm front hits the North Sea region near Westerhever, northern Germany, on August 11, 2014. (Photo by Daniel Reinhardt/AFP Photo/DPA)

Firefighters pull a pig as they try to rescue it from a well at a pig farm in Huanghua township of Leqing, Zhejiang province, April 25, 2014. Seven local firefighters successfully rescued a 300 kg (661 lbs) pig which fell down a well on Friday morning, local media reported. (Photo by Reuters/China Daily)

Three Chinese soldiers at the time of a civil war in China. (Photo by General Photographic Agency/Getty Images). 1922

In this February 2, 2015 photo, tourists jump as they pose for a picture, after disembarking from the Ocean Nova cruise ship, on King George Island, Antarctica. This tourist season, which runs November through March, more than 37,000 visitors are expected to walk on the coldest continent on Earth, about 10 percent more than the year before. (Photo by Natacha Pisarenko/AP Photo)

Carnival revellers dressed as “Peliqueiros” run along a street in the village of Laza, Spain February 11, 2018. “Peliqueiros”, or ancient tax collectors, pursued villagers through the streets ringing their cowbells and hitting villagers with their sticks. (Photo by Miguel Vidal/Reuters)

Kaye Don seated in the cockpit of his new racing car the “Silver Bullet” at Wolverhampton, England on February 21, 1930, in which he will attempt to beat world land speed record at Daytona. It has two 12-cylinder V shaped engines and each develops 2,000-h.p. The theoretical speed of the car is 275 m.p.h. but the designer estimated that will be able to reach 250 m.p.h. allowing for wind pressures. (Photo by AP Photo/Staff/Puttnam)

More than 6 billion people live in countries where serious levels of public sector corruption are fueling inequality and exploitation, according to Transparency International's 2015 index of perceived public sector corruption. The group's annual report measures perceptions of corruption due to the secrecy surrounding most corrupt dealings. Two thirds of the 168 countries assessed were identified as having a serious corruption problem. Somalia, which has been mired in conflict since civil war broke out in 1991, ranks bottom of the list. (Photo by Feisal Omar/Reuters)

Germany's Kira Walkenhorst (L) taps Germany's Laura Ludwig during the women's beach volleyball qualifying match between Germany and Canada at the Beach Volley Arena in Rio de Janeiro on August 9, 2016, for the Rio 2016 Olympic Games. (Photo by Leon Neal/AFP Photo)