I first saw this a few years ago and was intrigued at the time but then forgot about it, being elderly.
I’ve since seen it a few times, it being in my favourite part of Madrid and the last time, a couple of months ago, I decided to try and find something out about it.
This vertical garden, or living wall was designed by somebody called Patric Blanc (a French botanist it seems) in 2008. It contains over 250 different species with over 15000 plants that all seem to grow well, even in the harsh dry climate that exists in Madrid, especially in the summer.
Curiously it seems to generate its own sort of micro climate, I had noticed it previously whilst walking around it, but after having done a bit of research, my feelings were confirmed. The temperature around the wall, during the middle of the day, is several degrees lower than from where I took the photos.
Its strange to see this in the middle of a capital city, but its welcome and looks stunning.
By the way, should you ever happen to be there and see it, move 50 yards to the left and there is a terrifying overhanging roof, from memory a civic building, that I avoid like the plague, convinced its going to fall down.