Track and field moves to center stage Saturday morning as Jamaican Usain Bolt and American Justin Gatlin begin their duel for the 100-meter dash and the unofficial title of the "World's Fastest Human."
Bolt has won the last two Olympic gold medals in the 100, and he would like to make it three in a row at Rio. Gatlin has been a worthy challenger, and he would finally like to get the best of Bolt in Olympic competition.
The men's 100-meters heats will get underway, and so will the women's 400-meter events.
We will be here at 8:30 a.