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)

Durga Kami, 68, who is studying tenth grade at Shree Kala Bhairab Higher Secondary School, walks with his classmate Sagar Thapa, 14, as they head to school in Syangja, Nepal, June 5, 2016. (Photo by Navesh Chitrakar/Reuters)

A hippopotamus performs during a show at the circus in Krasnoyarsk, Siberia, Russia, July 7, 2016. (Photo by Ilya Naymushin/Reuters)

Highly commended birds : Crested guan by Tim Hunt (UK). ‘This photo shows a crested guan in the cloud forests of Costa Rica as it pauses while foraging on a lone branch. Due to the clouds that are so typical for this habitat, I could often only photograph the bird’s silhouette against a grey sky. But then, for a short moment only, the sun broke through the clouds, and I overexposed the image by over two stops in order to blow out the background and allow this beautifully marked bird to stand out’. (Photo by Tim Hunt/GDT European Wildlife Photographer of the Year 2015)

A Palestinian man walks down snow-covered stairs after Friday prayers near the Dome of the Rock on the compound known to Muslims as Noble Sanctuary and to Jews as Temple Mount, in Jerusalem's Old City February 20, 2015. Snow covered Jerusalem and mountainous areas of Israel early Friday morning and the education ministry closed schools for the day. (Photo by Ammar Awad/Reuters)

Floating on clear deep water and reflections near the cave entrance. Visitors can either bring their own kayaks or rent boats from the local community to paddle deep inside the cave and marvel at its wonders on March 2015 at Tham Khoun Ex, Laos. Tham Khoun Xe, commonly known as the Xe Bang Fai River Cave, in Laos, has over 15km of passages filled with awe-inspiring views and wide expanses of water. Photographer, John Spies, 59, captured scenes from the entrances of the huge underground river passages, intricate cave formations and views from a passage high above the water. The cave is formed by the Xe Bang Fai river, a major tributary of the Mekong and in the dry season can be traversed using inflatable kayaks. (Photo by John Spies/Barcroft Media/ABACAPress)

Mexicans dressed as French soldiers carry handcrafted guns, ahead of a reenactment of the battle of Puebla between Zacapoaxtla Indians and the French army during Cinco de Mayo celebrations in Mexico City, Tuesday, May 5, 2015. Monsalvo said he has been portraying Napoleon III in the annual neighborhood event for 28 years. Cinco de Mayo commemorates the victory of an ill-equipped Mexican army over French troops in Puebla on May 5, 1862. (Photo by Rebecca Blackwell/AP Photo)

An alpaca chewing a leaf is pictured on November 18, 2014 in the zoo of Frankfurt am Main, Germany. (Photo by Frank Rumpenhorst/AFP Photo/DPA)