The marble clocktower, or horologion, in the Roman Agora in Athens had multiple purposes in the ancient world: sundial, water clock, broadcaster and monitor of the winds. Horologion rethinks this architectural structure in terms of atmosphere and ambience. On each hour on the hour from October 2-26, 2014, an urban wind composed of city sound, light, mist and clouds rushes in, through, and out of Raumlabor’s temporary architectural structure, throwing open the window to the world. Water as timekeeper—sound to light to vapour to wind—all in real time.