Michael Phelps Swims His Final Individual Race, Winning…

…the gold medal, of course! Michael Phelps won the 100-meter butterfly at the London Olympic Games today, grabbing the record 17th gold, and his 21st medal overall in his entire Olympic career, reports the Associated Press.

The 100-meter butterfly was the final individual race of Phelps’ career, and his gold win marks a milestone in an impressive and monolithic Olympic run. Though he lagged some, and was the penultimate swimmer to turn in the event, he kicked his usual last-stretch overdrive, clocking-in at 51.21 seconds. Phelps’ career will be officially over after the 4×100 medley relay tomorrow, reports Newser.

Other noteworthy wins today: Missy Franklin set a world record in the 200 backstroke, earning her third gold and fourth medal overall. Katie Ledecky, the 15-year-old American wunderkind, won the 800-meter freestyle, almost landing a world record for her troubles. The youngest member of the U.S. swim team fell off pace on the last lap, finishing in 8 minutes, 14.63 seconds.

Great Britain’s Rebecca Adlington, though taking second-seat to Ledecky, still made the old country proud, earning bronze, amounting to a historic feat:

And just in case there’s any under-appreciation of Ledecky’s accomplishments, SwimmingWorld summed up her impact on the sport quite nicely with this tweet:

It’s been an eventful day for swimming at the 2012 London Olympics, with more records and real-time updates at BleacherReport. Did you see Michael Phelps’ last race?