Josh Kerr made history on Saturday at the London Diamond League, running 3:42.66 to break Hicham El Guerrouj’s legendary world record in the mile (3:43.13) from 1999. Kerr, a two-time Olympic medalist from Great Britain, announced his plans to go after the record in March, and since then, he’s steadily built anticipation for the event. Every step of the process was done with intention. He structur...