The Museu Nacional d'Art de Catalunya collected walls. Between 1919 and 1923 teams were sent into the Pyrenean valleys to strip paintings off the insides of village churches. The method is called strappo: cloth is glued to the surface and pulled, and the colour layer lifts away while the plaster stays behind. The apses were then rebuilt at full size inside the museum and the paint laid back onto the same curve. So you stand beneath the Christ of Sant Climent de Taüll, painted in 1123, at the height and in the shape it was made for.
An Italian restorer, Franco Steffanoni, was brought in to teach the technique to the Junta de Museus, the public body then assembling Barcelona's collections. The removals are still argued over, because the valleys lost paintings that had been in their churches for eight hundred years. The museum fills the Palau Nacional, put up on the flank of Montjuïc for the exposition of 1929, which is why it is far grander than a collection needs. Beyond the Romanesque rooms it runs on through Gothic altarpieces, baroque painting and rooms of modern Catalan art.