Some powerful rulers of the world may dream of the possibility to get in touch with their colleagues on different continents unnoticed by friends or foes. Someday, new quantum technologies could allow for making these wishes come true. Physicists around the world are working on the realization of large scale quantum networks in which single light quanta transfer (secret) quantum information to stationary nodes at large distances. Such quantum networks’ fundamental building blocks are, for example, quantum repeaters that counteract the loss of quantum information over large distances, or quantum logic gates that are necessary for processing quantum information.