Seven Days to the River Rhine (Russian: «Семь дней до реки Рейн», romanized: "Sem' dney do reki Reyn") was a top-secret military simulation exercise developed at least since 1964 by the Warsaw Pact.

It depicted the Soviet Bloc's vision of a seven-day nuclear war between NATO and Warsaw Pact forces.

[2][4] The files released included documents about "Operation Danube", the 1968 Warsaw Pact invasion of Czechoslovakia in response to the Prague Spring.

[7][8] The scenario for the war was NATO launching a nuclear attack on Polish and Czechoslovak cities in the Vistula river valley area in a first-strike scenario, which would prevent Warsaw Pact commanders from sending reinforcements to East Germany to forestall a possible NATO invasion of that country.

[2][3] Maps associated with the released plan show nuclear strikes in many NATO states, but exclude both France and the United Kingdom.

Britain, which has always been at the heart of NATO, would also have been spared, suggesting Moscow wanted to stop at the Rhine to avoid overstretching its forces.

To that end, the Headquarters and two divisions of II (Fr) Corps were permanently stationed in West Germany, with the wartime mission of supporting NATO's US-led Central Army Group (CENTAG).

The plan indicates that USAF fighter-bombers, primarily the long-ranged F-111 Aardvark, would be employed in nuclear strikes, and that they would be launched from those British bases.