Once again, the world's focus is on the Olympic Stadium in Berlin as Usain Bolt and Tyson Gay look to reach the final of the men's 200m. There are four world titles on offer, including the men's 1500m, where the African nations are expected to feature prominently. Olympic champion Dawn Harper will be hoping to add a world title to her list of accolades in the 100m hurdles, while the countries from the former Soviet bloc look to have a stranglehold in the women's 1500m. Meanwhile, Olympic hammer champion Gerd Kanter of Estonia is attempting to successfully defend his world title.