Forum Flora Germanica

The spines are actually really short, looks longer on image. And all turned downwards.
Thick spines, relatively, I think, as you can pick up thing with bare hand and nothing stays in skin.

Cereus could be totally wrong (matches only no. of ribs, at this point).

http://agrozoo.net/jsp/Galery_one_image ... bdbf0a8ec4

EDIT: Pachycereus marginatus looks like a match.

Hmm. first image here has 7 ribs, is that a variable ? https://en.wikipedia.org/wiki/Lophocereus_marginatus

Lophocereus marginatus will be right. 7 (8) and also 5 ribs occur.