MEXICO CITY -- Legendary sports feats tend to echo over time, in the process resonating with those who were not around to celebrate in real time. It's why younger fans of the Miami Dolphins raise a figurative glass each season when the last NFL team without a loss eventually falls, free to celebrate an oft-cited tradition of the 1972 squad -- the only team to ever finish a season undefeated.
Fifty years after those Dolphins entered the record books, they continue to inspire lore (E60's "The Perfect Machine" on the '72 Dolphins debuts at noon ET Sunday on ABC and will be available on ESPN+ afterward).