And in a time of increased vigilance, there's a question of whether more cameras are needed.
Rep. Peter King, R-NY, chairman of the Homeland Security Subcommittee on Counterintelligence and Terrorism, thinks so.
"I do favor more cameras, they're a great law enforcement method and device, and it keeps us ahead of the terrorists who are constantly trying to kill us," King told MSNBC.
King's view wins some support among people asked about whether more cameras in public places could help prevent attacks like Monday's bombings in Boston that killed three and injured hundreds.
"I thought we had enough cameras but evidently we don't," says Del Shawn, a District resident.
Juana Cerna, of Aurora, Colo., a freshman at American University also favors more cameras to keep an eye on public places.
"I think it's a good idea," she says.
"I come from Aurora where the shooting was and I lost a friend."
Cerna says the Newtown, Conn., shootings and now the bombings in Boston are scary and perhaps more cameras would help people feel safer.
Some people argue that increasing the number of cameras simply may not be effective in countering terrorism, contending that it's human intelligence -- tips to the police -- that have averted attacks.
Others worry that more cameras could further erode people's privacy.
"Privacy is an important right in this country, and I think we should be very careful about how much surveillance we submit ourselves to," says Gerry Elliott, a resident of the Ingleside at Rock Creek retirement home in D.C.
But King says more public cameras don't invade privacy.
"Privacy involves being in a private location. Being out in the street is not an expectation of privacy, anyone can look at you, can see you, can watch what you're doing," But, King told MSNBC.
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