Eurovision Song Contest 1964 (partially found broadcast footage; 1964)
The 1964 Eurovision Song Contest was the ninth annual contest held in the Tivoli Concert Hall in Copenhagen, Denmark on March 21st of 1964. The contest was inspired by the Sanremo Music Festival, a contest hosted in Italy annually, and was started in 1956 (the footage from the 1956 event is also lost).
The contest was hosted by Lotte Waever and the show consisted of 16 countries performing one song each with an interval act performed by the Ballet-Harlequinade and finally the reprise of the winner's song. The winner that year was 16 year old Gigilola Cinquetti hailing from Italy and sang the song "Non ho L'eta" scoring a total of 49 points (compared to second place United Kingdom with only 17 points).
The contest was overshadowed by a protest that occurred during the show. The 1964 contest was Portugal's debut Eurovision contest and was very politicized with protesters demanding that the right-wing dictatorships of Spain and Portugal to be excluded from the contest. During the show, before the performance of the Belgian entry, a man entered the stage and held up a sign saying "Boycott Franco and Salazar" (Franco being the Caudillo of Spain and Salazar the Prime Minister of Portugal at that time). The camera panned to a shot of the scoreboard and once the man was gone, the show went on.
Even though there were multiple cameras for the many Europeans at that time that possessed televisions, the footage of the contest is lost. The host broadcaster, DR's (Danmarks Radio) studios had a fire in the 1970's that destroyed the tape of the Eurovision Song Contest 1964. Also, none of the other broadcasters had recorded a tape of the show leading it to obscurity. Supposedly, the BBC had a tape canister of the 1964 contest labeled, "Eurovision 1964" during a storage cleanup, however, the tape is missing and is presumably wiped.
The full radio broadcast and intact photos of the contest are found and can be easily found online. The only footage of the contest as of now, is the reprise of the song, "Non ho L'eta" filmed by an audience member and a few segments of the show from the German broadcasting network, NDR, that exist. (Gigliola Cinquetti's first performance are shown in the third video (14:57-15:36) and the few segments from NDR are shown throughout the first video)
EDIT: I came across the opening of the contest plus a few scenes from the beginning of the show. The footage is from the host broadcaster, DR. It also shows the footage of the reprise from the perspective of the man who filmed it. The footage of the full contest, including the footage of all the performance of the participants, are still, unfortunately, missing. There is also a video (2nd video) with some behind the scenes footage and the history of ESC 1964, however, the video is in Danish.