19 May 1942.
As they had done each May 19th since 1924, the BBC recorded nightingales singing in the late evening in a place called Foyle Riding in Surrey.
The nightingales were not all that they recorded:
105 Wellingtons, 31 Stirlings, 29 Halifaxes, 15 Hampdens, 13 Lancasters and 4 Manchesters of RAF Bomber Command were on their way to attack Mannheim in Germany. The drone as they flew overhead was also captured by the BBC.
Of the 197 aircraft that flew over Foyle Riding that night, 11 failed to return. Only light damage resulted from the raid. Most of the target photographs from those that did make it to Mannheim showed forests or open fields.
(Hat tip to Chris Wild of ‘How to be a Retronaut’)