Airglow with gravity waves. Airglow is a faint emission of light, usually green, that is caused by several atomic processes in the upper atmosphere. (Atmospheric) Gravity waves are oscillations of the stable upper atmosphere due to an updraft. Possibly, the updraft, that specific day, was caused by big fires around that area. Gravity waves are visible thanks to airglow in this image taken at Sounion, Attica on 18/7/2015.
<a href="//commons.wikimedia.org/w/index.php?title=User:Christos_Doudoulakis&amp;action=edit&amp;redlink=1" class="new" title="User:Christos Doudoulakis (page does not exist)">Christos Doudoulakis</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>