Dennis Kipruto Kimetto has run 2:02:57 to win the 2014 Berlin Marathon, taking 26 seconds off the previous World Record and becoming the first man under 2:03, beating the ineligible 2:03:02 set at Boston in 2011. He is Kenyan, as is the second place getter with the third placed runner being Ethiopian.
The Ethiopia-Kenya corner of the world has produced an extraordinary proportion of top male and female marathoners in the last twenty years. This article at sportsscientists.com/ shows that the source of these runners is even more specific, with most runners coming from the Kalenjin tribe. Both Kimetto and Wilson Kipsang, the previous record holder, are Kalenjin.
A count of the best 112 times of 2013 sees 61 Kenyans, 37 Ethiopians, and 3 Eritreans. A Moroccan runner was in position 59 with a Japanese runner at position 62.
In 1990 the best time was 2:08:16 by Steve Moneghetti, also at Berlin. Had that time been run in 2013 it would have been the 107th fastest time.
Just incidentally, there were a claimed 40,004 entries for the 2014 Berlin.