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Look to the sky later because it's a really big day for the RAF in London.
They're marking 70 years since Sir Winston Churchill gave his 'The Few' speech during the Battle of Britain.
A Spitfire and Hurricane - planes which protected London during World War 2 - will fly over the Cabinet War Room in Whitehall at around 4pm.
On the way they'll pass other important sites including Biggin Hill, Croydon and RAF Northolt.