High Quality Content by WIKIPEDIA articles! The Men`s 50 Butterfly at the 10th FINA World Swimming Championships (25m) was swum 17 – 18 December 2010 in Dubai, United Arab Emirates. On December 17, 119 individuals swam in the Preliminary heats in the morning, with the top-16 finishers advancing to swim again in the Semifinals that evening. The top-8 from the Semifinals then advanced to swim the Final the next evening.