New York, NY —

Mayor Michael Bloomberg visited London Tuesday on a fact-finding mission about its massive surveillance camera system, known as the ring of steel, in the wake of the failed car bombing attempt in Times Square.

The mayor, with London Mayor Boris Johnson, viewed a control room, where experts were monitoring cameras positioned in London's underground train system. Authorities say the city's Tube system is watched by more than 12,000 cameras, compared to the 4,000 in New York City's subways.

Bloomberg says it wasn't clear whether more cameras in Times Square would have thwarted Faisal Shahzad's alleged effort to set off a car bomb, but the mayor says the presence of additional cameras might have discouraged the suspect from trying.