In this Friday, February 6, 2015 photo, sandhill cranes begin to stir after resting for the night at a roosting location along their winter migration route in Cecilia, Ky. According to counts made by biologists with the Kentucky Fish and Wildlife Resources, about 12,000 of the birds have stopped in Cecilia this week during their winter northward migration on their way to their nesting grounds in the Great Lakes region. (Photo by David Stephenson/AP Photo)

A bunker at aformer Swiss artillery fortress called Heldsberg stands near the town of St. Margareten, Switzerland March 22, 2015. Heldsberg fortress, located on the Swiss-Austrian border near the River Rhine and Lake Constance was built from 1938 to 1940 and remained in military use until 1992. Since 1993 it is open to the public as Fortress Museum Heldsberg. (Photo by Arnd Wiegmann/Reuters)

The 30th anniversary of the meltdown at the Chernobyl nuclear plant that caused large amounts of radioactive particles to be released into the air will be commemorated on April 26, 2016. Photojournalist Sean Gallup returned to the area to document the lasting effects of the world's worst nuclear power plant accident. Pictured, children's beds are seen in an abandoned kindergarten in Kopachi village located inside the Chernobyl exclusion zone, September 29, 2015, near Chernobyl, Ukraine. (Photo by Sean Gallup/Getty Images)

British underwater photographer of the year – winner. “Love Birds” by Grant Thomas (UK). Location: Luss Pier, Loch Lomond, Scotland. Thomas’s initial idea was to frame a split shot of one swan feeding below the surface of the water but when he noticed how comfortable they were around him he was confident, with some patience, he could get that magical shot of the two. (Photo by Grant Thomas/UPY 2018)

Sri Lankan flood victims flock around a bus to receive food parcels on a inundated road in Colombo, Sri Lanka, Tuesday, May 17, 2016. The Disaster Management Center said that 114 homes have been destroyed and more than 137,000 people have been evacuated to safe locations as heavy rains continue. (Photo by Eranga Jayawardena/AP Photo)

A man walks on a slackline during the 7th edition of the European “Marmotte Highline Project” (MHP) festival in Lans-en-Vercors, near Grenoble, eastern France, on July 4, 2019. The event, during which the participants will be able to evolve on the various highlines located in the Regional Natural Park of Vercors, takes place until July 7, 2019. (Photo by Philippe Desmazes/AFP Photo)

“7584 Fish”. On a windy day right after a Cyclone passed the far northern Great Barrier Reef i took some friends out to the reef. Never before i saw that many glass fish on this particular coral “bommie”. Just when i setup my camera, this Napoleon Wrasse swam right through the school of fish building a living frame. Photo location: Cairns, Great Barrier Reef, Flynn Reef, Australia. (Photo and caption by Christian Miller/National Geographic Photo Contest)

Films that are being screened are advertised in a makeshift cinema located under a bridge in the old quarters of Delhi, India May 25, 2016. A makeshift cinema hall under a 140-year-old bridge in the Indian capital is allowing poor rickshaw pullers and migrant labourers to escape daily hardship and sweltering heat into a world of Bollywood song, dance and romance. With the rusty iron floor of the bridge as its ceiling and some old rags acquired on the cheap from a nearby crematorium serving as curtains and floor mats, the cinema shows four films a day. (Photo by Cathal McNaughton/Reuters)