When the Soviet Union broke up in the early 1990s, weapons-grade material went missing from several of its nuclear facilities. This map shows data from the International Atomic Energy Agency that reveal the movements of that material across Europe over the following years. Each symbol marks a case in which smuggled weapons-grade nuclear material was intercepted and reported to the agency.

Interceptions peaked in the mid-1990s, but almost a kilogram of highly enriched uranium has been seized in Georgia over the past five years. The agency says such cases indicate the “parlous state of security of radioactive material”.