It's hard to say how long it could have taken the FBI to find the Boston suspects if so many cameras hadn't been rolling.
If something happened in D.C., it would be the same story in busy areas. Take Chinatown.
It may not surprise you that a busy neighborhood like Chinatown has a lot of cameras. But it may surprise you just how many over the next block or so are capturing our image.
When you walk down 7th Street, you're constantly on camera. Verizon Center's watching you and Gallery Place has plenty of cameras too. Clyde's Restaurant alone has two near the entrance.
Then there's less obvious ones outside a bar, an entrance to condos or the ATM.
Police say they use the cameras all the time to fight and solve crime.
Many locals are glad they're there.
"The fact that it could pick up on any suspicious activity in the neighborhood makes this place a lot safer," says Shlomo Fishman of Silver Spring.
But some say having more than 20 cameras in less than two blocks is too much.
"It's just weird. I feel like they're just staring at me," says Estefania Delgado, a visitor to Chinatown.
Others say if anything they'd like to see more.
"I'd rather have a thousand cameras considering what happened in Boston," says Penna Pringle, who works in Chinatown.