Behind the Skin - East Wing, National Gallery of Art, Washington DC

Its not often you get to see what is underneath the skin of a famous landmark building. Currently the East Wing of the National Gallery of Art, designed by the architect I.M Pei, is undergoing a reconstruction and the limestone cladding has been removed, and beneath it is revealed the concrete frame structure and brick infill.  

A fascinating look behind the curtain don't you think?