at a waterworks in Berlin Tegel.
Groundwater is ventilated to
induce flocculation of iron and
manganese in order to remove
these substances by filtration.
At the same time the low air
pressure causes hydrogen
sulphide (from decomposition
processes in the ground) and
carbon dioxide to escape.

>> I almost made a fool of
myself here: I had seen images
of other ventilation towers
and had already made up my
mind about the kind of picture
I wanted to take. But when I
saw this tower, it looked
completely different! I couldn’t
do the picture I wanted. I even
felt I couldn’t do any pictures
at all and was about to leave.
Foolishly! I can but thank my
assistant for persuading me
to stay and shoot anyway:
GEO liked this picture so
much, they made it a spread!