The nuclear weapons launch site in San Cristobal that sparked the Cuban Missile Crisis was modelled on one at Plokštinė in Lithuania, which opened on New Year’s Eve 1961. The disused installation is no longer top secret – it’s now a museum – but it is still out of the way. Overlooked by dense pine forests, the silos yawn with ominous promise, like thermonuclear wishing wells. Each of the SS-4 rockets that might once have roared out of them had more than half the firepower used throughout the Second World War, including Hiroshima and Nagasaki. A single warhead could have flattened London within ten minutes of take-off.