The sound comes from the Jericho Trumpet, a siren fitted to the Junkers Ju 87 Stuka dive bomber during the Second World War to create fear as the aircraft dived. The siren was driven by airflow over small propellers on the undercarriage, producing its distinctive screaming tone. After the war, recordings of the dive became a familiar stock effect in war films, documentaries and later video games, where it was often used for any falling bomb. That long association with danger and impending impact keeps it instantly recognisable in memes and edits today.