Carnival revellers carry burning wooden sticks during the traditional Swiss Chienbaese celebration in Liestal near Basel February 22, 2015. (Photo by Ruben Sprich/Reuters)

An autumn leaf sticks to a bench near the Bishops Castle near Wells Cathedral on November 1, 2011 in Wells, England. According to a number of nature watchers the autumn colours are currently reaching their peak following an unusually warm September and October which has led to trees holding onto their leaves longer than normal. (Photo by Matt Cardy/Getty Images)

A South Korean military vehicle drives past barricades at the military check point, near the Demilitarized zone (DMZ) separating South and North Korea on December 20, 2011 in Paju, South Korea. (Photo by Chung Sung-Jun/Getty Images)

Head of the department of the interior architecture at Estonian Academy of Arts Hannes Praks poses for a picture in the wooden megaphone in the forest near Pahni village, Estonia, September 28, 2015. (Photo by Ints Kalnins/Reuters)

A man walks through the morning mist in a park in Rozzano, near Milan, northern Italy, Thursday, December 17, 2015. (Photo by Antonio Calanni/AP Photo)

Military enthusiasts take part in a re-enactment of the World War II battle of Stalingrad at the “Stalin Line” memorial, near the village of Goroshki, Belarus, February 27, 2016. (Photo by Vasily Fedosenko/Reuters)

A migrant tries to restrain her tent from strong winds in a makeshift camp for refugees and migrants at the Greek-Macedonian border near the village of Idomeni, Greece, March 24, 2016. (Photo by Alexandros Avramidis/Reuters)

An aircraft passes over houses at it lands at Heathrow Airport near London, Britain, December 11, 2015. Picture taken December 11, 2015. (Photo by Neil Hall/Reuters)