Boston Marathon security: How can you keep 26.2 miles safe?

STORY HIGHLIGHTS

• Two suspicious bags were spotted on the one-year anniversary of the attacks
• A man carrying one of the bags was charged with possessing a hoax device
• Runners will not be allowed to wear backpacks in this year's Boston Marathon
• Large signs, costumes and unregistered runners will also be banned 
• (CNN) -- As thousands gathered to mark the one-year anniversary of the Boston Marathon bombings, one sight evoked memories of the attack that spurred widespread carnage: suspicious bags near the finish line.
  
  Police spotted the bags on Boylston Street -- not far from where two pressure-cooker bombs exploded exactly one year ago Tuesday, killing three people and wounded at least 264 others.
  Eventually, both bags spotted Tuesday were deemed safe -- but the man carrying one of the bags has been charged with possessing a hoax device.
  But how are police preparing for this year's marathon, which takes place Monday? Given that the 26.2-mile course runs through eight cities and towns, how can police possibly prevent every suspicious item from slipping through



People pause Tuesday, April 15, as the American flag is raised at the finish line of the Boston Marathon, where two homemade bombs went off one year ago. It was the deadliest terrorist attack in the United States since 9/11.

• http://edition.cnn.com/2014/04/16/us/boston-marathon-security/