“Aurora Hunters”. Photographers taking part in a photography tour on the Lofoten Islands in Norway, pull over on the side of the road to take a photo of their first ever Aurora Borealis after spotting it from their tour bus. Photo location: Rystad, Lofoten Islands, Norway. (Photo and caption by Mark Gee/National Geographic Photo Contest)

Russian President Vladimir Putin, right, and North Korea's leader Kim Jong Un pose for photographers during their meeting in Vladivostok, Russia, Thursday, April 25, 2019. Putin and Kim are set to have one-on-one meeting at the Far Eastern State University on the Russky Island across a bridge from Vladivostok. The meeting will be followed by broader talks involving officials from both sides. (Photo by Alexander Zemlianichenko/AP Photo/Pool)

A child walks to an installation made from fallen leaves by college students, in shape of a sofa, to call for people's attention to environment protection, in Hangzhou, Zhejiang province, China, December 6, 2016. (Photo by Reuters/China Daily)

A couple embrace during the start of the San Fermin festival in Pamplona, Spain July 6, 2016. Revelers from around the world kick off the festival with a messy party in the Pamplona town square, one day before the first of eight days of the running of the bulls. (Photo by Vincent West/Reuters)

A ranger of Kenya Wildlife Services (KWS) tries to cover the eyes of 2.5-year-old female Southern white rhino, Elia, to calm down after being shot a tranquilizer from a helicopter during Kenya Wildlife Services (KWS) rhino ear notching exercise for identification at Meru National Park, 350 km from Nairobi, Kenya, on April 5, 2018. (Photo by Yasuyoshi Chiba/AFP Photo)

Festival goers having fun at the Balaton Sound music festival in Zamardi next to the Lake of Balaton, 110 km (68 miles) west of Budapest, July 6, 2017. (Photo by Zsolt Furesz)

A reveller takes part in an annual block party known as “Cordao de Prata Preta”, one of the many carnival parties to take place in the neighbourhoods of Rio de Janeiro, February 6, 2016. (Photo by Pilar Olivares/Reuters)