Cities are filled with hidden landscapes of data. Wi-Fi signals surround us at all times, but they remain invisible, until now. A group of Norwegians have developed a method for visually representing Wi-Fi signals around us. They achieved this by building a four metre Wi-Fi measuring rod with lights that represent the power of the signal. When the rod is fully lit it means the signal is at full strength. Long exposure photography shows how the signal varies as you move; they tested the device in Oslo, Norway. Check out the stunning results in the video below.