A concept illustration of the world's first forest in the sky, the Bosco Verticale green twin towers currently under construction in Milan, Italy. Towering over the city skyline the world's first forest in the sky will be a sight to behold. With tree equal to one hectare of forest spanning 27 floors these 365 and 260 foot emerald twin towers will be home to an astonishing 730 trees, 5,000 shrubs and 11,000 ground cover plants. (Photo by Boeri Studio)

First lady Michelle Obama (R), joined by daughters Sasha Obama (C) and Malia Obama, is presented with the official White House Christmas Tree on November 25, 2011 in Washington, DC. The tree, a 19-foot-tall balsam fir, was grown on Schroeder's Forevergreens farm near Neshkoro, Wisconsin. (Photo by Brendan Hoffman/Getty Images)

Six month- old baby elephant “Clear Sky” is kept afloat with the help of a harness during a hydrotherapy session at a local veterinary clinic in Chonburi Province on January 5, 2017. After losing part of her left foot in a snare in Thailand, baby elephant 'Clear Sky' is now learning to walk again – in water. (Photo by Roberto Schmidt/AFP Photo)

The Tibetan night sky was captured in these beautiful images showing the stunning buildings and statues in the Himalayan mountains. Grey Chow, 33, traveled for two hours to get to the Spiti Valley to capture the starry backdrop along the isolated, deserted roads. The senior project engineer was able to take amazingly clear images thanks to the limited amount of pollution at the 4,500-foot (1371m) altitude. (Photo by Grey Chow/Caters News Agency)

A girl sits on a pile of rubbish at landfill site on the outskirts of Sanaa, Yemen November 16, 2016. (Photo by Mohamed al-Sayaghi/Reuters)

A girl takes pictures after opening ceremony at Shanghai Disney Resort in Shanghai, China, June 16, 2016. (Photo by Aly Song/Reuters)

A Bangladeshi girl plays on a swing, in Dhaka, Bangladesh, December 27, 2016. (Photo by Mohammad Ponir Hossain/Reuters)

Two girls in cosplay dresses walk in the street in Beijing on March 27, 2017. (Photo by Fred Dufour/AFP Photo)