I was refering to the size of the factory premises = land + buildings.

It seems we need diffrent categories for a ranking: premises vs. base area of the buildings vs. floor area of the buildings vs. largest building per base area vs. largest building per floor area, etc. And then we would need to clarify what counts in each case ...

Anyway, I live about 20 km from BASF and it is quite an impressive sight, especially at night. Here is a photo: https://de.m.wikipedia.org/wiki/Datei:Fackelschein_des_Steam... However, the red lights are probably an artefact of the camera; typically the lights looks rather bluesh in reality. And the photo was shot with a 400 mm lens: the television tower in the foreground is more than 4 km away from the factory, the house at the left about 3 km.

I've studied in the area and, as a bit of a night person, often drove past at night when driving to or from parents. A very cool sight, though the smell is often less pleasant :D - presumably nothing toxic, that would be illegal, but it does smell bad. Kind of like burning plastic, but without the harshest components of that smell.

Anyway, cool that Germany still has the biggest of something ~heavy industry.

Like an image ripped from Blade Runner.