So, you know, check in with people. Or just read this photo essay on the Mental Floss blog: "10 Abandoned Psych Wards Photographers Love Sneaking Into."
About the image at left:
Cane Hill was a massive asylum on the outskirts of London, opened in 1882 and closed in 1991. Since then it’s been extremely popular with urban explorers (as well as arsonists), who damaged the place so badly that most of it had to finally be torn down back in January. Which is a shame — it was really something. Photographer Richard James took this impressive shot of the asylum chapel.