A man is seen trapped amid the debris of an under-construction flyover after it collapsed in Kolkata, India, March 31, 2016. Using saws, small cranes and bare hands, rescuers on Friday cleared the crumbled concrete and twisted steel from an overpass that collapsed onto a crowded Kolkata neighborhood, killing at least 23 people and injuring more than 80. With more than half the debris cleared by Friday morning, 67 people have been pulled out alive, police said. (Photo by Rupak De Chowdhuri/Reuters)

People, carry food and water, past a tractor stuck in mud, stones and debris that were piled in a flood in the mountain village of Sipkovica, just above the town of Tetovo, in northwestern Macedonia, on Tuesday, August 4, 2015. A small number of people including children have died in floods that erupted after an hour of heavy torrential rains and strong winds that hit Tetovo and northwestern region of Macedonia late on Monday. (Photo by Zoran Andonov/AP Photo)

A grey whale greets tourists in boat in, Baja California, Mexico, March 2017. A pair of newly born grey whale calves intrigued by visiting tourists eagerly swim over to the group to get a closer look. Urged on by their mother, the small calves confidently went up to the tour group who were visiting San Ignacio Lagoon in Baja California, Mexico. This adorable moment was captured by zoologist and wildlife photographer, Mark Carwardine on his visit to the area in March 2017. (Photo by Mark Carwardine/Barcroft Images)

File photo taken on July 24, 2011 shows the scenery of karst landform in Dacai Township under Maonan Autonomous County of Huaijiang, south China's Guangxi Zhuang Autonomous Region. The World Heritage Committee on Monday inscribed an extension of South China Karst, a natural World Heritage Site since 2007, into the UNESCO's World Heritage List. (Photo by Wang Xiufa/Xinhua)

Papier-mache pandas, created by French artist Paulo Grangeon, are covered with conical hats as they are displayed under the rain at the financial Central district in Hong Kong June 21, 2014. The installation arrived in the city on Monday, launching the month-long “1600 Pandas World Tour in Hong Kong: Creativity meets Conservation” organized by a local art organiser, according to the official press release. (Photo by Tyrone Siu/Reuters)

A workman sweeping the highest sidewalk in the world, the 81st story of the Empire State Building, the world's tallest building, to the top of which the greatest dirigible “Los Angeles” will attempt to moor, New York, New York, early 1930s. This photo was made 1,248 feet above street level. (Photo by Adam Glickman/Underwood Archives/Getty Images)

Swiss grass skier Stefan Portmann in action during a free practice at the Grasski World Championships in Marbach, Switzerland, 13 August 2019. About 80 participants from 10 nations will start at the Grasski - World Championships, which will take place from 13th to 18th August 2019. (Photo by Alexandra Wey/EPA/EFE)