Art in the airport in Madrid, Spain

We changed planes in Madrid and even at 4 in the morning the airport is gorgeous.  The interior is full of organic forms.  For instance, the ceiling looks like a billowing canvas supported by stylized trees.  There is a feeling of openness and relaxation in what is really a long straight tube containing many gates for planes.  What's more, the airport even appears to be functional (unlike Paris Charles de Gaule which is currently a nightmare to navigate).  You get off one plane, are whisked to another terminal on a rapid tram, are directed to your gate area through clearly visible signs which are often even in English!  One thing you should know - the gate for your next flight isn't assigned until about 50 minutes before boarding.  Instead you are directed to a waiting area near many gates (just like Mexico City airport).  That makes a lot of sense to me.  There is no worry that the gate may change if the flight is delayed.  In Madrid, once the gate is assigned, that's where the plane will be.