First place in the 2021 IAU OAE Astrophotography Contest, category Light pollution. Light pollution results from the excess of artificial light produced by human endeavours mainly as a side effect of industrialisation. This kind of pollution is usually most noticeable around well populated areas associated with intense human activities, such as street lighting, lights from the transportation system, buildings and houses. But it can also come from other places, such as ships and oil platforms in the sea. This image taken in a national park in Belgium in 2018 shows the detrimental effect of light pollution on the most precious resource that connects all humans together – the night sky. Credit: Dong Han/IAU OAE