Porsche 917/20 'Pink Pig', one of three 917s run by Martini International Racing Team in the 1971 24 Hours of Le Mans. Number #23, driven by Reinhold Joest (later founding Joest Racing in 1978) and Willi Kauhsen.
(https://www.porsche.com/stories/innovation/what-is-the-porsche-pink-pig/)