Sea of clouds is seen after a rainfall at the Huangshan Mountain scenic spot on April 10, 2019 in Huangshan, Anhui Province of China. (Photo by Fang Lihua/Qianlong.com/VCG via Getty Images)

A woman holds thre dogs by a make shift leash amongst the debris left behind by a tornadon on February 7, 2017 in New Orleans, Louisiana. (Photo by Sean Gardner/Getty Images)

People look at a man, who residents said was killed by al Qaeda militants, hanging on a bridge in Yemen's southeastern city of Mukalla June 17, 2015. Al Qaeda militants in Yemen killed two alleged Saudi spies, residents said, accusing them of planting tracking devices which enabled the assassination of the group's leader in a suspected U.S. drone strike. (Photo by Reuters/Stringer)

Zulmira Jesus poses for a portrait at a street in Povoa de Agracoes, near Chaves, Portugal April 19, 2016. In the villages of Agracoes and Povoa de Agracoe, the steady drip-drip of emigration has brought down population numbers from more than 50 residents to fewer than a dozen each. These remaining villagers share the same glum acceptance that, after they have gone, their villages will die out too. It is the same desolate picture in scores of other backwater settlements in Portugal's interior, north to south. (Photo by Rafael Marchante/Reuters)

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)

A statue of a man sleepwalking in his underpants is surrounded by snow on the campus of Wellesley College, in Wellesley, Mass., Wednesday, February 5, 2014. The sculpture entitled “Sleepwalker” is part of an exhibit by sculptor Tony Matelli at the college's Davis Museum. (Photo by Steven Senne/AP Photo)

When a French politician remarked that a monument should be raised in honour of American independence at a dinner party in 1865 he probably didn't imagine that the result would become an international icon of freedom. ...