Eliud Kipchoge is already the fastest marathoner ever with his 2:00:25 from Monza in May. Four months after that, he'll try to break the world record in an officially sanctioned race. He announced today that he is racing the Berlin Marathon in September, and the race said this morning in a press release that it would be a world record attempt. (Kipchoge's time from the Nike Breaking2 event in Monza was not sanctioned because of various techniques that are not normally permitted, including a car bringing him water and a phalanx of pacemakers substituting in and out for each other.)

The official marathon world record is 2:02:57, run by Dennis Kimetto in Berlin in 2014. Berlin is the best course in the world for a men's marathon world record attempt; the last six men's world records have all been set there, dating back to Paul Tergat's 2:04:55 in 2003.

Six of the ten fastest men's marathons ever run were in Berlin, and six out of eight if you take out the wind-aided runs from the 2011 Boston Marathon.

Kipchoge's 2:03:03 personal best is only six seconds shy of the current world record. 2:02:57 is 4:41.5 mile pace for 26.2 miles.