Abandoned Skyscrapers in Sao Paulo?

[STERNyc]

I was browsing the Sao Paulo page at Urban Decay

http://www.urbandecay.ca/

And noticed what looks to be a number of abandoned skyscrapers. The early modernist architecture of these buildings indicate they were built sometime in the 50's or 60's. Im wondering if there's more and what the story is behind them.











I've seen extensive urban decay elsewhere but never on this scale. Urban decay usually follows certain lines on fringe neighborhoods and the established neighborhoods that urban decay infringes on are usually low-rise residential or industrial neighborhoods. I have never seen urban decay of this scale in a Buisness District. It looks like these abandoned skyscrapers once had a hey-day, or atleast thats what it looks like, I would love to know the back story.