Strange building on the way to Barcelona

I captured this very strange looking building through the train window on my way by high-speed train from Marseille to Barcelona. The train was moving slow enough that I was able to get a reasonable shot, using the little EM-10. The Canon was wrapped and packed away in my bags!

I suspect the strange lattice steelwork was meant as a cover for an even uglier looking structure behind. Any suggestions as to what was behind the lattice?