In which year did the Battle of Britain have its 80th anniversary?

The 80th anniversary of the Battle of Britain was in 2020.

The Battle of Britain was a military campaign of the Second World War, in which the Royal Air Force and the Fleet Air Arm of the Royal Navy defended the United Kingdom against large-scale attacks by Nazi Germany's air force, the Luftwaffe. It was the first major military campaign fought entirely by air forces. The British officially recognise the battle's duration as being from 10 July until 31 October 1940.

The primary objective of the German forces was to compel Britain to agree to a negotiated peace settlement. In July 1940, the air and sea blockade began, with the Luftwaffe mainly targeting coastal-shipping convoys, as well as ports and shipping centres such as Portsmouth.

Historian Stephen Bungay cited Germany's failure to destroy Britain's air defences to force an armistice (or even an outright surrender) as the first major German defeat in the Second World War and a crucial turning point in the conflict. The Battle of Britain takes its name from the speech given by Prime Minister Winston Churchill to the House of Commons on 18 June: "What General Weygand called the 'Battle of France' is over. I expect that the Battle of Britain is about to begin."