A traffic police woman whistles at a pedestrian, Monday, July 27, 2015, in Pyongyang, North Korea where its citizens are having a one-day national holiday to celebrate the country's 62nd anniversary of the armistice that ended the Korean War. (Photo by Wong Maye-E/AP Photo)

Michal Navratil of the Czech Republic performs after the men's 27 meter high dive final at the Swimming World Championships in Kazan, Russia, Wednesday, August 5, 2015. (Photo by Denis Tyrin/AP Photo)

A woman sits next to a Gollum figure on the “Middle-earth Shuttle” subway train November 18, 2003 in New York City. The train's cars were decorated with Middle-earth creatures, vines, moss and stones to celebrate the November 18 DVD and VHS release of the Special Extended Edition of The Lord of the Rings: The Two Towers. (Photo by Mario Tama/Getty Images)

“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)

“Rosslyn Chapel, properly named the Collegiate Chapel of St. Matthew, was founded on a small hill above Roslin Glen as a Roman Catholic collegiate church (with between four and six ordained canons and two boy choristers) in the mid-15th century. Rosslyn Chapel and the nearby Roslin Castle are located at the village of Roslin, Midlothian, Scotland”. – Wikipedia

Photo: The interior of Rosslyn Chapel on February 9, 2012 in Roslin, Scotland. Built between 1446 and 1484 it is a category A listed building, covered in ornate stonework and carvings of individual figures and scenes. People travel from all over the world to visit the chapel which many have described as an architectural wonder and a library in stone. Many theories, myths and legends associated with the Chapel have given it a unique sense of mystery and wonder. (Photo by Jeff J. Mitchell/Getty Images)

Students from CAS Ballet Theatre School stretch on the sidewalk Saturday, February 20, 2016, in Ann Arbor, Mich. (Photo by Junfu Han/The Ann Arbor News via AP Photo)

People participate in a pillow fight to mark International Pillow Fight Day in the Heroes' Square, in central Budapest, Hungary, Saturday, April 2, 2016. The Pillow Fight Day attracts tens of thousands people in more than 100 cities all over the World each year. ((Photo by Zoltan Balogh/MTI via AP Photo)

A Iranian man walks with a sheep he bought at a market in the capital Tehran on September 12, 2016, as Muslims mark the first day of the Eid al-Adha (Feast of the Sacrifice) holiday. Muslims across the world celebrate the annual festival of Eid al-Adha, or the festival of sacrifice, which marks the end of the Hajj pilgrimage to Mecca and commemorates prophet Abraham's readiness to sacrifice his son to show obedience to God. (Photo by AFP Photo/Stringer)