I notice one of your replies above mentions a desire to see Buzludzha in winter: so here are some pics from the aforementioned trip with Kamen. The snow was up to our thighs and it was the most post-apocalyptic scene I've ever laid eyes on. I've also never seen snow like that and I was terrified. My jacket wasn't up to snuff. We couldn't break in, we found a tunnel into it but I wussed out, in case we couldn't climb back out.