Can you really smile while you’re swimming? Most of us, I’d imagine, would fill our ducts with rivers of chlorine. But Michael Phelps, who has gills for something, has no problem grinning in the pool. With about 20 m left in the 4 x 200-m freestyle relay in London on Tuesday night, Phelps knew he had it: he was about to win a gold medal, the 19th Olympic medal of his career, breaking the record held by former Soviet Union gymnast Larisa Latynina. “I started smiling,” Phelps says. “I don’t think I’ve ever done that in a race before.”