Barajas Airport is so inspiring, a vibrating place to come and go. Love to walk in its roller stairs and watch the organic columns and the wavy ceilings changing colors from blue to yellow designed by the architects Richard Rogers and Estudio Lamela.
One of my favourite places to enjoy a beer bathed in orange lights and layered walls. They used to give concerts downstairs. Unfortunately they got recently banned due to boring local regulations - hopefully, live music will return soon amongst their palm trees and tropical lights.
Reina Sofia museum is always a good idea. And it's never enough of Picasso's Guernica as well as the other modern art gems. Save some hours for visiting and then look round the corner and have some wine at NuBel.