Boston Police officers, Lt. Colm Lyden (left) and Sgt. Steve Downs, walked the marathon route under the Massachusetts Avenue Bridge on Commonwealth Avenue before the racers arrive.
Along the route
Boston Police officers, Lt. Colm Lyden (left) and Sgt. Steve Downs, walked the marathon route under the Massachusetts Avenue Bridge on Commonwealth Avenue before the racers arrive.
(Globe Staff Photo / Pat Greenhouse)