A darknet is a set of unused IP addresses whose monitoring is an effective way of detecting malicious activities on the Internet. We have developed an alert system called DAEDALUS (direct alert environment for darknet and livenet unified security), which is based on large-scale darknet monitoring. This paper presents a novel real-time 3D visualization engine called DAEDALUS-VIZ that enables operators to grasp visually and in real time a complete overview of alert circumstances and provides highly flexible and tangible interactivity. We describe some case studies and evaluate the performance of DAEDALUS-VIZ.