A New York Police Department officer and a bomb sniffing dog patrol the finish line area before the start of the New York City Marathon in New York, November 3, 2013. In addition to cheering supporters, runners in this Sunday's New York City Marathon will also be monitored by bomb-sniffing dogs, police scuba divers and surveillance helicopters to prevent an attack similar to the one at the Boston race earlier this year. (Photo by Mike Segar/Reuters)
