Children enjoy a sledge ride past ice swimming fans at the Zalew Zegrzynski lake in Nieporet, Poland, Sunday, February 25, 2018. A cold wave hit Poland with the temperature minus 8 degree Celsius (17.6 Fahrenheit) during the day and dropping to minus 16 degree Celsius (3.2 Fahrenheit) in the night in central Poland. (Photo by Alik Keplicz/AP Photo)

A wide-angle view shows the ascent of the shuttle Challenger on January 28, 1986. In the seconds after ignition, the rocket engines' hot blast began the process of destruction. (Photo by NASA)

Female of pygmy hippopotamus called Malaya from Netherlands in zoo in Dvur Kralove nad Labem, Czech Republic, February 22, 2016. (Photo by David Tanecek/CTK via ZUMA Press)

Children play football in Bujumbura, Burundi on March 19, 2015. (Photo by Carl de Souza/AFP Photo)

Vladimir Putin shows a hold to a young judo wrestler at the Regional Judo Center at the Arena Sports Complex in the Siberian city of Kemerovo on January 24, 2012, during his visit to the region. Putin is known for his passion for judo, in which he has a black belt. (Photo by AFP Photo/STR)

A man standing on the first cables during the construction of the Golden Gate Bridge with the Presidio and San Francisco in the background, San Francisco, California, 1935. (Photo by Underwood Archives/Getty Images)

Cast member Ana de Armas poses during a photocall for the film “Hands of stone” out of competition at the 69th Cannes Film Festival in Cannes, France, May 16, 2016. (Photo by Regis Duvignau/Reuters)

A picture made available 26 April 2016 shows a tiger playing in the water with a trainer nicknamed “Super Tiger Man” at the Tiger Temple in Kanchanaburi province, Thailand, 24 April 2016. The site known in Thai as “Wat Pa Luangta Maha Bua Yannasampanno” has been the focus of a dispute with the Department of National Parks, Wildlife and Plant Conservation (DNP) after the DNP asked in 2015 that the temple hands over its 147 tigers since it was not licensed to keep them. The temple has requested for a zoo license according to its managing director. (Photo by Diego Azubel/EPA)