Tucson Mayor Jonathan Rothschild rang a bell at the downtown fire station 19 times Tuesday morning to note the moment two years ago when Jared Lee Loughner opened fire.

Rothschild rang the bell one time for each of the six people killed and 13 wounded in the attack at a meet-your-congresswoman event being held by former Rep. Gabrielle Giffords.

Church bells and other bells rang throughout the city at 10:10 a.m. Tuesday, when the shooting broke out two years earlier.

Killed were 9-year-old Christina-Taylor Green, U.S. District Judge John Roll, Giffords' staff member Gabe Zimmerman and three constituents, Dorwin Stoddard, 76, Dorthy Murray, 76, and Phyllis Schneck, 79.

Giffords was critically wounded in the attack, and she resigned from Congress last year. Also wounded was Ron barber, her district office director. Barber ran for and won Giffords' seat in a special election in June and then was elected to a two-year term in November.