Michael Phelps returns from retirement

Michael Phelps, the most decorated swimmer of all time, announced in April that he would come out of retirement to swim at a U.S. meet later that month, the first step toward possibly swimming at the 2016 Rio Olympics.

Phelps returned to training last fall and re-entered the U.S. drug-testing program. He has completed his six-month waiting period by the U.S. Anti-Doping Agency to be eligible for competition.

The 18-time Olympic champion claimed his first international gold medal as part of the U.S. 4x200m freestyle relay at the Pan Pacific Championships in August, just four months into his comeback.