Took this in colour then converted to B/W and fiddled with the contrast. Welcome to comments: I reckon the contrast tweak may be too heavy-handed.

Interesting composition. To make the shot a bit more stormy, I would apply a graduated neutral filter to the clouds, e.g. brown, before desaturating.

Moody and great textures.

Wow, very cool! Nice wall!

Thanks to all. gsum, I'll try what you've suggested and see how it turns out. I've basically no idea about editing so all tips are helpful.

I especially like that wall. Reminds me of Andy Goldsworthy's work.