be a story this year. what's going to be the story? >> journalist steve silva is covering the event for boston.com. >> it was a normal day and a good day. >> sydney corcoran with her mom and dad are among the 1 million spectators enjoying the day. >> my family and i went into boston and got a bite to eat and made our way down to the finish line. >> 30,000 runners had spent months preparing to cross this line. >> opposite boston across the charles river, two brothers are also preparing for the marathon in a much more sinister way. tamerlan tsarnaev and his younger brother dzokhar live in an unremarkable house on an unremarkable street. they've been working on a recipe from an online magazine. it's called inspire, the english language terror guide created by