The power of lighting.
[youtube=http://uk.youtube.com/watch?v=-dFOphuPqMo]
In the Weather Project, Olafur Eliasson turned the huge Turbine Hall at the Tate Modern into a sunset, his main conceptual driver was the way we talk about the weather and experience it in our everyday lives. In the run up to the opening of the installation he interviewed the gallery staff to find out what they thought about the weather. He displayed the statistics as part of the publicity as a talking point. This was both a good way of getting people involved and talking about the project and a commercially astute piece of advertising. It is interesting that the most talked about thing was the power of the atmosphere and the shared experience of lying on the floor underneath the mirrored ceiling, the conscious conversation about the weather became an aside. A poignant moment came when, in response to the Madrid train bombings on March 11, 2004, a group spelt the word Spain by arranging their bodies on the floor of the Turbine Hall to the applause of everyone else in the gallery. The atmosphere was electric as it was 10pm on the last day of the exhibition, dark outside but inside the light of hundreds of sodium lamps reflected in the ceiling mirrors made a warm glow and the reflections of all the people who had stumbled into this strange, calming, apocalyptic scene were reflected in the ceiling as tiny dots within the vastness of the turbine hall. It is interesting also, to note the way in which groups gathered together on the floor in an attempt to define themselves apart from the mass of tiny dots.
from : http://www.lightmodulator.org/research-interaction.htm