Career Highlights: The most successful swimmer in Brazilian history, Cielo heads to London looking to defend the gold medal he earned with an Olympic-record time of 21.30 in the 50m freestyle at the Beijing Games. Cielo also won bronze in the 100m freestyle in the 2008 Olympics, but that event appears to be an afterthought as he prepares for London. Though he's the current world record holder in both the 100m and 50m, Cielo plans to devote most of his attention to the 50m for the 2012 Olympics after what he deemed a "very slow" 100m performance in the Brazilian Olympic trials in April. Cielo, who won six national championship events in three years at Auburn University, tested positive for the banned substance furosemide in May 2011. Though furosemide is a diuretic generally used to help lose weight, it also can be a masking agent that is capable of hiding the presence of other drugs. Cielo was given a warning by FINA, though an arbitrator ruled he was still allowed to compete in the 2011 world championships in Shanghai. He didn't disappoint, winning gold in both the 50m freestyle and butterfly events.