Descending through the artifacts, Powers of Ten-like, we pause finally, hovering above the city, rapt with attention. I could spend all day exploring this Google Earth, but it strikes me that there's a couple of extensions I'd like to see. Neither of which are easy, but why should that stop idle speculation?
Whilst pawing Barcelona around - incidentally, what an awkward combination of movements Google Earth engenders? Grabbing, dragging, clawing, zooming, revolving, tilting. A haptic interface would seem more suitable to the object - I realised how well the application describes the form of the city. The beautiful, rigorous grid of the Eixample is clearly discernible, block after block interlocking neatly with those unique chamfered corners. At street level, the variegation in architecture and generous spacing disguises this economic, adaptable layout. In Google Earth, the traces of ancient city walls are perceptible too, a serrated edge separating the density of the Ciutat Vella from the Eixample.

My overwhelming sensation at this point was a desire to slide the city back through its development, to watch the port developments shrink back on to land, to see the Eixample retreat block by block, to watch the city walls rise up again ... And then slide it forward. I'm still reading Joan Busquets' Barcelona: The Urban Evolution of a Compact City which is no doubt influencing my thinking. Combined with Barcelona's expressive form, it's too compelling a desire.