Swimming great Michael Phelps takes a final bow at the Olympics on Saturday while the Rio curtain rises on another legend as sprinter Usain Bolt guns for three golds.

Jamaican Bolt enters the Rio fray in the heats of the men’s 100m while Phelps, the most decorated Olympian in history, is expected to clinch the 23rd gold medal of his career in the 4x100m medley.