Risen What is that thing…

I got up there through the commandant's building with the help of levitation - but as I try to climb on the architecture itself I go through it, get stuck walking in it (with clipping problems) and the game stops responding to me (unless I end up gliding through to the other side...falling to my death).

Is there any way to get inside there ? Is there anything in it ? Is the model of the dark fort a "prop" or does it play a more important part in the next chapters ? Should I know this before time ? Should I be asking this question at all ?!?!

the feet of the colossus?

I didn't know you can reach that point. If you can fall through the wall you're not supposed to be there I guess Did you find any items or even plants up there? It's not part of any quest or the story, it's rather a bit dissapointing that you don't get any info about it in the game. First I thought this might once have been a titan. But once you progress to the end of the game …
Maybe you could make a screenshot

It never hit me as being two giant feet…I just thought the construction crew cut corners during the building process and ended up with deformed towers…