This was
your sky.

Contrail Shadow X

A giant 'X' appeared in the clouds over Istanbul, Türkiye, created by the shadows of contrails. Contrails form when humid engine exhaust from airplanes freezes into water droplets and ice crystals in the cold upper atmosphere. These streams scatter sunlight, appearing bright, and can cast long shadows. Contrails occur globally and generally warm Earth by trapping infrared light.