The Boston Marathon is an extraordinary spectacle. Between 500,000 and a million spectators line the 26.2-mile course annually, making the marathon one of the world's most widely viewed one-day sporting events, according to estimates by police and public safety officials from the eight cities and towns along the route. And as if that were not enough, in terms of on-site media coverage, the Boston Marathon ranks behind only the Super Bowl as the largest single day sporting event in the world. More than a thousand media members, representing more than 250 outlets, have requested media credentials for the 110th running of the race this coming Monday. That's a big deal.