I was a schoolboy in Twickenham in 1947 when the headmaster told the assembled pupils that we would be hearing a big bang as thousands of tons of unexploded ammunition were exploded on the island of Heligoland off the German coast. ISTR we did hear a bang (of sorts) at the appointed time, but it was certainly not loud.
Heligoland Operation Big Bang 1947
More here:
https://www.bbc.co.uk/news/world-europe-39590752