1) Extended to the max 2) For the most time 3) Guinness superlative 4) Least short 5) Long 6) Longer 7) Maximally protracted 8) Most enduring 9) Most extended 10) Most extensive 11) Most protracted 12) Most tedious 13) Of greatest duration 14) Tops in endurance Found on https://www.crosswordclues.com/clue/longest