This applied research extends a tradition among artists who have sounded out infrastructural elements. For the centennial of the Brooklyn Bridge, in 1983, Bill Fontana mounted eight microphones under the bridge’s steel grid roadway and broadcast live sounds at the World Trade Center plaza. In 1999, Stephen Vitiello spent six months in residence on the 91st floor of the World Trade Center, recording how Tower One swayed and creaked with the wind. Such works make sensible the micro-rhythms and macro-scale physical stresses that infrastructures withstand and amplify the distinct mechanics of their materials and construction techniques. 44 Other artists have encouraged listening to technical and media infrastructures, such as WiFi networks, cell connections, and the global positioning system. Since 2004, Christina Kubisch has hosted “Electrical Walks” in several dozen cities. Participants wear specially designed headphones that translate electromagnetic signals into audible sounds, disclosing the waves and particles — generated by activities like ATM transactions and CCTV surveillance — which perpetually envelop and penetrate urban bodies. Similarly, Shintaro Miyazaki and Martin Howse use logarithmic detectors, amplifiers, and wave-filter circuits to transform electromagnetism into sound, revealing the “rhythms, signals, fluctuations, oscillations and other effects of hidden agencies within the invisible networks of the ‘technical unconscious.’” 45