Dancers attend a dress rehearsal for the new grand show “THE WYLD” at Friedrichstadt-Palast in Berlin October 2, 2014. Ten choreographers are working with 60 dancers from the world's largest show ballet company to create the flamboyant stage spectacle. The show's name, “THE WYLD”, represents human nature in its diversity and the wilderness of the big city – in this case, Berlin. The premiere of the 10.6 million euro ($13.5 million) show, the largest production budget in the 95-year history of Friedrichstadt-Palast, is on October 23, 2014. (Photo by Hannibal Hanschke/Reuters)

“Contrails (short for “condensation trails”) or vapour trails are artificial clouds that are the visible trails of condensed water vapour made by the exhaust of aircraft engines. As the hot exhaust gases cool in the surrounding air they may precipitate a cloud of microscopic water droplets or, if the air is cold enough, tiny ice crystals”. – Wikipedia

Photo: An airplane leaves a vapor trail as it flies in front of he moon on January 17, 2007 above Hanover, Germany. (Photo by Alexander Hassenstein/Getty Images)

These are the dunes of the Namib Desert, taken by Korea's Kompstat-2 satellite. The blue and white area is the dried riverbed of the Tsauchab river. (Photo by The European Space Agency)

After 12 years photographing models, musicians, and celebrities, Brad Wilson decided that he wanted to photograph something a little more unpredictable: wild animals. Photo: Serval. (Photo by Brad Wilson)

A model showcases designs on the catwalk during Beijing Institute of Fashion Technology and Taiwan Shin Chien University Graduates Collection show of China Fashion Week A/W 2011 on March 25, 2011 in Beijing, China. (Photo by Feng Li/Getty Images)

A model presents a creation made with chocolate by professional designers and pastry chefs during a Chocolate Fashion Show at the Salon Du Chocolat in Beirut, Lebanon November 12, 2015. (Photo by Jamal Saidi/Reuters)

“Environmental Migrants: The Last Illusion” by photographer Alessandro Grassani, documents the life of people in Kenya, Mongolia and Bangladesh who migrate to escape environmental stresses to the city of their own countries in hopes for a better life. Here: Asia, Mongolia, March 27, 2011. A view of Ulaan Baator over the shoulder of a slumbering drunk. Alcoholism is a huge problem in the city, home to almost half of Mongolia's people. The capital's population has doubled in the past two years. High levels of unemployment and poverty await herders who abandon rural areas and arrive in the city, illiterate and untrained in any skills necessary for urban jobs. (Photo by Alessandro Grassani)

Young Palestinians form an obstacle to be jumped over during a military-style exercise graduation ceremony organised by the Hamas movement, in Gaza City August 5, 2015. Thousands of young Palestinians joined Hamas military-style summer camps during school vacation in the Gaza Strip to prepare them to “confront any possible Israeli attack”, organisers said. (Photo by Suhaib Salem/Reuters)