As a teenager (about 1981) I was on a family holiday in Alsace, France when we stopped at one of the large barge locks on the Rhein south of Karlsruhe.
The balmy summers afternoon peace was broken by a strange noise approaching from the north.
A few seconds later a large formation of 4 diamonds of Canadian F104s (16 aircraft) and a single diamond of T33s (4 aircraft) appeared at about 1500 ft heading south towards Baden-Soellingen which was a few miles south of us.
A wonderful sight and a wonderful noise!
I am guessing it was maybe Families Day at Soellingen.