Interiors are not permanent artefacts. Rather, they are ephemeral experiences and temporary enterprises. Some interiors last for just a moment. Others may endure for centuries; but they will all disappear in the end, leaving behind only the lightest of traces.

The Old Town of Edinburgh is a historic architectural monument, fixed in heavy stone; but for a brief few weeks each year it is infected by hundreds of temporary interiors, as the performers and producers of the Fringe and the Edinburgh Festival seek out nooks and crannies in which to pursue their evanescent arts. Dark streets, vaults, corners, alleys spring into noisy, colourful life for the month of August, only to relapse into dormancy with the onset of the autumn. Two timescales, one measured in centuries, the other in minutes, clash within in a tiny spatial and temporal compass, reminding us that the built environment is not, as Goethe once said ''frozen music'' but merely music that is playing very slowly over time.

Between 29th August - 12th September 2009, as the Edinburgh Festival drew to a close, students and academic staff from all over Europe and beyond met at Edinburgh College of Art to investigate and celebrate the unique collision of permanence and temporariness that make a summer in the Old Town of Edinburgh.

Students were divided into ten groups, listed below, and each group was asked to investigate the site, and all the problems and opportunities it holds, in terms of a particular timescale. Click on the timespan below to see what they achieved