I came across these abandoned buildings by accident when I was photographing a park in North Ridgeville, Ohio. I think they may have been a garden center or conservatory originally. With this image, I used the control points in Nik Silver Efex Pro to highlight the rusty cogs and pipes.

Pentax K-30
Pentax smc DA 18-270mm f/3.5-6.3 ED SDM

1/400th @ f7.1, ISO 400, 270mm.