TWAN is an international effort to photograph nightscape and time-lapse videos of the world’s landmarks. According to TWAN's website "The contest was founded by TWAN and Dark Skies Awareness project in 2008 as a regional program. It was expanded to an international effort in 2009 during the International Year of Astronomy, and it is growing each year."
Criteria for the contest is that the submitted images are all created by showing both the Earth and sky with a notable scenery or landmark. Known as “Landscape Astrophotography” this is similar to general "Nightscape Photography" but with more attention to the sky, astronomical perspectives, and celestial phenomena. The contest was in collaboration with the Global Astronomy Month and National Optical Astronomy Observation.
The contest aims to reclaim the natural beauty of starry sky and to help preserving the dark skies which are not yet dominated by artificial lights.
Via Huffington Post