The new "Caixa Forum" in madrid. Designed by Swiss architects Herzog & de Meuron and the french designer Patrick Blanc (Vertical Garden).
unfortually it wasn't open to the public when i was in Madrid, so i didn't get to see the interior.
H&deM at archINFORM: http://eng.archinform.net/arch/291.htm
Patrick Blanc: http://www.verticalgardenpatrickblanc.com/