Wysteria is a type of flowering vine (having grape-like bunches of flowers when in bloom) that you can literally watch grow. I left my truck window down while parked next to a wysteria-covered wall and overnight the vine grew in through the open window and around the steering wheel. This type of vine has been known to split tractors apart and lift out other plants (full grown trees included) as many invasive species have been known to do., so Puddleboy's comment about the vine pulling down the pole is completely within reason.

Went there last night, guys, BE CAREFUL! You know about the cops, you know about the health threats and you want to know about the ghosts, but be aware there are some REAL people there who will not just arrest you or scare the crap out of you. There are junkies there and they will protect their stash by any means necessary. Consider yourself lucky if you've made it in and out of those buildings in one piece as of late.
I love the photos and the stories as much as the next person, but the people there are getting to be enough of a deterent. Nonlethal tasers and pepper spray are your best bet in self-defense if you must go, but I highly recommend NOT going inside at night.
Very insightful comments on here though, thank you everyone for sharing your experiences!