Urbexing is usually quite easy in Berlin, but the Kabelwerk (cable factory) is a noteworthy exception. That has to do with the fact that most parts of the building will be demolished soon and replaced by expensive homes, so there is permanent security on-site, who in the end managed to find and expel us.
It obviously didn’t stop us from exploring 50% of the former cable production halls, and the exquisite graffiti there. The site itself, along the river, is gold as well. So be quick or regret missing out!