The Swiss Light Source (SLS) is a synchrotron located at the Paul Scherrer Institute (PSI) in Switzerland for producing electromagnetic radiation of high brightness. Planning started in 1991, the project was approved in 1997, and first light from the storage ring was seen at December 15, 2000.The experimental program started in June 2001 and it is used for research in materials science, biology and chemistry. As of June 2009 SLS has eighteen experimental stations (undulators and bending magnets) and seventeen operational beamlines.