“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)

With the entry of Poland into the European Union in 2004, Warsaw is currently experiencing the biggest economic boom of its history. The opening match of UEFA Euro 2012 is scheduled to take place in Warsaw. (Photo by: ryarwood; Source: Flickr)

Poznań is now Poland's fifth largest city. It is sometimes claimed to be the first capital of the kingdom of Poland. Poznań has many historic buildings and sights. The European Football Championship will take place in Poznan 2012.

Photo by: tiseb ; Source: Flickr

A view of fluffy toy bears displayed for attraction outside the windows of a hotel in Yantai in Shandong province Thursday, January 6, 2022. (Photo by Tang Ke/Future Publishing via Getty Images)

People take part in a military exercise for civilians conducted by veterans of the Ukrainian National Guard Azov battalion, amid threat of Russian invasion, in Kyiv, Ukraine on January 30, 2022. (Photo by Gleb Garanich/Reuters)

British singer-songwriter Raye (L) during The BRIT Awards 2021 at The O2 Arena on May 11, 2021 in London, England. (Photo by JMEnternational/JMEnternational for Brit Awards/Getty Images)

Paul Poirier of Canada and Marjorie Lajoie of Canada after training before the Figure Skating Ice Dance – Rhythm Dance at Capital Indoor Stadium in Beijing, China on February 12, 2022. (Photo by Aleksandra Szmigiel/Reuters)

The hair of CSKA Moscow cheerleaders flies high as they perform during the Euroleague Basketball game between Alba Berlin and CSKA Moscow in Moscow, Russia, 04 February 2022. (Photo by Yuri Kochetkov/EPA/EFE)