Key point: The Soviets had nuclear weapons.
The Nazis conquered France in six weeks, in one of the most spectacular military victories in history.
Had the Soviet Union gone to war with the West in the early 1960s, it also planned to blitz France. But unlike the Germans, the Soviets planned to do it in a week, according to the Warsaw Pact's 1964 war plan, discovered in the military archives of the former Czechoslovakia.
Was this an example of military might or military megalomania? For a system that professed not to believe in God, the Soviet plan appears nothing short of miraculous. Put simply, all the Soviets and their Eastern European allies had to do was launch their offensive from Czechoslovakia, smash through southern Germany, cross the Rhine River, and then drive into southern France. All this to be accomplished in about seven days, or as long as God took to create the Earth. And even He needed to take a rest at the end.
The Soviet plan was nearly as ambitious. It called for the Czech First and Fourth Armies to push for the Franco-German border, while the Soviet Eighth Guards Army advanced on their northern flank and the Hungarians on their southern flank. Paratroopers would seize crossings over the Neckar and Rhine Rivers. The Warsaw Pact tanks and mechanized infantry were expected to thrust about 700 miles from Czechoslovakia to Besancon, about 150 miles northeast of Lyon, by D+8. From there, the Soviets could thrust north to Paris and the Channel ports, or south to the Mediterranean ports such as Marseilles.
To strike from Czechoslovakia to Besancon would require the Red Army to travel around 60 miles per day. To put this in perspective, one of the most rapid advances in history was made by Rommel's Afrika Korps in June 1942, when German mechanized units routed the British Eighth Army and advanced 350 miles in 10 days, or 35 miles per day. Even during the 1940 German blitz that devastated France, Rommel's famed 7th Panzer Division advanced only 85 miles in five days.