In 1916, MIT crossed the river from its original location in Boston’s Back Bay to Cambridge, taking up residence on the banks of the Charles. Since then, generations of students have trekked across the bridge, including Oliver Smoot and his fraternity brothers, who left their indelible mark along the way. LightBridge is a dynamic display symbolic of MIT’s historical and contemporary connections between people and places on both sides of the river. This participatory installation allows people to use a website to design their own interactive light effects in advance and then experience their designs on site on May 7 and 8 as part of FAST Light at MIT's 2011 Festival of Art, Science and Technology. The 10,000 pixel display is activated by sensors (proximity sensors, cameras, buttons, microphones, mobile phones) that respond to the movement and activities of viewers in the area. By combining sensors and programmable lighting, the project illustrates the potential for user-driven urban screens and new configurations of low-resolution displays that blur the boundaries between traditional city lighting and the responsive infrastructures of tomorrow. Thanks to Philips ColorKinetics for donating the LED light strips, CISCO for providing the network hardware, and SparkFun Electronics for donating additional electronics for the sensor network. The project is funded in part by a grant from the Council for the Arts at MIT. MIT Festival of Art, Science and Technology. FAST Light 2011. Video by Judy Daniels.