Polar bear twins make their first public appearance with their mother “Freedom” at Ouwehands Zoo Rhenen, in Rhenen, The Netherlands, 19 February 2015. The twins, who were born in November 2014, have not been named because their gender has not yet been determined. (Photo by Bart Maat/EPA)

A group of students sit on top of a bus at Kemusu street in Boyolali, Central Java of Indonesia, March 20, 2015 in this picture taken by Antara Foto. (Photo by Yusuf Nugroho/Reuters/Antara Foto)

A young boy scoops water from a hand-dug well in the dry riverbed near Matinyani, in the semi-arid Kitui County in southeastern Kenya, 22 March 2015, the World Water Day. Residents of Kitui County and other arid and semi-arid areas of the country have been hard-hit by extremely poor rainfall this year while the government said in previous month that some 1.6 million people countrywide are facing acute starvation due to the drought and will need relief food over the next six months. Residents of Matinyani say they haven't seen a drop of rain in nearly four months. Thousands of Kenyans in rural areas walk tens of kilometers just to fetch water to drink and to be used in their homes. According to an estimate by UNESCO (United Nations Educational, Scientific and Cultural Organization), 17 million people lack access to safe water in Kenya, where the drought is a perennial problem. (Photo by Dai Kurokawa/EPA)

A picture taken with slow shutter speed shows members of the group “The Kattfiller” from Attendorn taking part during the Norddeutsche Championship carnivalesque dance sport in Kassel (Hessen), Germany, 28 February 2016. About 1,100 qualified dancers show in different disciplines their skills. (Photo by Swen Pfoertner/EPA)

A member of the Brotherhood of Gentlemen Legionnaires of Asturias feeds its mascot after the governing body of the “Estudiantes” brotherhood decided that penance could not be carried out in the streets due to rain on Palm Sunday in Oviedo, northern Spain, March 20, 2016. (Photo by Eloy Alonso/Reuters)

A fisherman carries a sailfish on his head to the fish market in Hamarweyne near the port of Mogadishu on April, 4, 2016. (Photo by Mohamed Abdiwahab/AFP Photo)

A woman cries as she stands next to house destroyed by the earthquake in the Pacific coastal town of Pedernales, Ecuador, Sunday, April 17, 2016. A magnitude-7.8 quake, the strongest since 1979, hit Ecuador flattening buildings, buckling highways along its Pacific coast and killing hundreds. (Photo by Dolores Ochoa/AP Photo)

The Villarrica Volcano is seen at night in Chile, April 16, 2016. Villarrica is one of Chile's most active volcanoes. Picture taken with long exposure. (Photo by Cristobal Saavedra/Reuters)