The mysterious underground maintenance tunnels of the University of Oulu gained unprecedented value as the expert team of the open 5G Test Network (5GTN) at the Centre for Wireless Communications invited specialists from Keysight Technologies – a leading innovator in electronic test and measurement equipment – and Nokia to perform underground measurements in the vast tunnel network. Surrounded by thick concrete structures, the nearly endless narrow alleys offer an attractive angle for measuring the capacity of the campus wide wireless network and specifically its IoT components.