BROOKLYN - More than 30,000 bikers took over the city today for the annual Five Boro Bike Tour, and the NYPD sharply stepped up security in the wake of the Boston Marathon bombings.

The tour gave participants the opportunity to cross bridges and roads that are normally limited to vehicles only. Many city streets were blocked off for the event.

At Brooklyn Bridge Park, volunteers handed out snacks and drinks to cyclists to keep them hydrated and energized.

The NYPD used mobile cameras, radiation detectors and extra patrols with its counterterrorism team to ensure security today. No backpacks were allowed.