Planes land in fog at Heathrow Airport, west London, as heavy fog covers a many parts of the south east, on April 1, 2014. (Photo by Steve Parsons/PA Wire)

Florin Bors, aged 8 from Bacau, northern Romania, wearing a bear fur takes a break from performing a holiday season ritual in Bucharest, Romania, Tuesday, December 16, 2014. In pre-Christian rural traditions, dancers wearing colored costumes or animal furs, touring house to house in villages singing and dancing to ward off evil. In recent years following the economic downturn in Romania, a European Union member since 2007, the tradition has moved to Romania's cities where dancers travel to perform the ritual for money. (Photo by Octav Ganea/AP Photo/Mediafax)

Spanish soldiers of the 7th Airborne Light Infantry Brigade “Galicia” fire a howitzer Light Gun L118 during maneuvers with other units in preparation to NATO's Very High Readiness Joint Task Force (VJTF) in Zaragoza, Spain, April 19, 2016. (Photo by Javier Cebollada/EPA)

In this October 21, 2015, file photo, a young man rides a hoverboard along a Manhattan street toward the Empire State Building in New York. More than 500,000 hoverboards are being recalled after reports that they can burst into flames. The Consumer Product Safety Commission said Wednesday, July 6, 2016, it has received 99 reports of battery packs in the two-wheel motorized scooters catching fire or exploding that causing burns or property damage. The recalled hoverboards were made by eight companies. (Photo by Kathy Willens/AP Photo)

A Selkirk Rex cat is one of more than 400 breeds of cats being presented at the World Cat Federation two-day show in Dortmund, Germany, on April 21, 2013. (Photo by Frank Augstein/Associated Press)

An Indian white tiger cools off in a pond in its enclosure at Chhat Bir Zoo on the outskirts of Chandigarh on May 22, 2016. Temperatures have soared to a scorching 51 degrees Celsius in one Indian city, meteorologists said, with the ferocious heat setting a new national record. Northern Phalodi wilted as the mercury reached a new high on May 20, equivalent to 123.8 Fahrenheit, beating a 60-year-old record. (Photo by Shammi Mehra/AFP Photo)

Jimmy Arnold, an overweight boy from Rochester, bites into a cake. (Photo by Reg Birkett/Keystone/Getty Images). 14th April 1951

Camp dwellers pump water from a well at Malkohi refugee camp in Jimeta, Adamawa State, Nigeria on February 19, 2019, four days ahead of the country's General elections set for February 23 after a last-minute rescheduling. Malkohi is a camp for internal displaced who fled their homes as Boko Haram insurgents advanced across north-eastern Nigeria. From their homes on the outskirts of Yola, capital of presidential candidate Atiku Abubakar's home state Adamawa, Malkohi residents say they feel forgotten. (Photo by Luis Tato/AFP Photo)