The world record in the mile run is the fastest time set by a runner in the middle-distance track and field event. World Athletics is the official body which oversees the records. Hicham El Guerrouj is the current men's record holder with his time of 3:43.13, while Sifan Hassan has the women's record of 4:12.33. Since 1976, the mile has been the only non-metric distance recognized by the IAAF for record purposes. However, in international competitions such as the Olympics the term "mile" almost always refers to a distance of 1,500 meters, which is 109.344 meters shorter than an Imperial mile, even though four "full" laps of a 400 meter track is equal to 1,600 meters. Accurate times for the mile run (1.609344 km) have been recorded since 1850, when the first precisely measured running tracks were built. Foot racing had become popular in England by the 17th century, when footmen would race and their masters would wager on the result. By the 19th century "pedestrianism", as it was called, had become extremely popular and the best times recorded in the period were by professionals. Even after professional foot racing died out, it was not until 1915 that the professional record of 4:12 (set by Walter George in 1886) was surpassed by an amateur. Progression of the mile record accelerated in the 1930s as newsreel coverage greatly popularized the sport, making stars out of milers such as Jules Ladoumègue, Jack Lovelock, and Glenn Cunningham. In the 1940s, Swedes Arne Andersson and Gunder Hägg lowered the record to just over four minutes (4:01.4) while racing was curtailed during World War II in the combatant countries. After the war, Roger Bannister of the United Kingdom and John Landy of Australia vied to be the first to break the fabled four-minute mile barrier. Roger Bannister did it first on May 6, 1954, and John Landy followed 46 days later. By the end of the 20th century, the record had been lowered to the time of 3:43.13 run by Hicham El Guerrouj of Morocco in 1999. On the women's side, the first sub-5:00 mile was achieved by the UK's Diane Leather 23 days after Bannister's first sub-4:00 mile. However, the International Association of Athletics Federations (IAAF) did not recognize women's records for the distance until 1967, when Anne Smith of the UK ran 4:37.0. The current women's world record is 4:12.33 by Sifan Hassan,