Map of Vienna highlighting districts, international organizations, and selected embassies in red. Notable sites near Donau River. Introduction: Last week, Austria expelled three Russian diplomats, accusing them of spying. Foreign Minister Beate Meinl-Reisinger declared that the Russian embassy staff were using an "antenna forest" on the roofs of diplomatic buildings in Vienna to gather information, an intelligence gathering technique known as SIGINT (Signals intelligence). Th