Mostly he walked. He walked all around London. Down narrow streets to Hyde Park, to the Thames River, to bustling Piccadilly Circus, hidden in the crowd like an anonymous tourist. "Just kind of hanging out, man," Barry Sanders said. He saw "Les Miserables," which he also saw in New York. He saw another show, but he couldn't remember which one. Occasionally, somebody would recognize him. But usually they did not. He met some students from the London School of Economics. They talked a little football. American football.

Back home, everybody wanted to know why Barry Sanders had disappeared.

This was a little more than 13 years ago, the summer of 1999, when Sanders, then 31 years old, still healthy, closing in on the all-time rushing record, decided to walk away from the NFL. The news was a shock to his league, his team, to the city of Detroit, and it took a long time for the story to sort itself out—how an adored superstar could suddenly leave a franchise he defined, with so much football talent presumably left.

But when I met Sanders the other day in New York, where he was in town to promote a traveling exhibit for the Pro Football Hall of Fame called Gridiron Glory, I wasn't interested in rehashing the reasons why he left the Lions, or the contract acrimony that followed. I wanted to know about London. I wanted to know how one of the game's greatest players had escaped a frenzy by vanishing across the Atlantic—by himself, no agent, no publicist, no entourage, a solo traveler. Like the man himself, the story of Barry Sanders's European retirement vacation had always been something of a mystery.

Sanders smiled. He is 44 now, still fit and trim under his yellow Hall of Fame Jacket. It'd been a long time since he'd thought about that trip. That was July of 1999, and the Lions were about to kick off training camp. His reps had told the Lions he wasn't coming back. And that's when he got on the plane, at Detroit Metro Airport.