(CNN) -- The thought came to Don Walker during that most quintessential of American outings -- a baseball game. Caught in a crush of people on his way into Atlanta's Turner Field, he couldn't help but think about what had just happened in Boston -- sports fans crowded into a small space, a bomb tucked into a backpack, and then death. Not that it stopped the Morgantown, West Virginia, man from enjoying his Atlanta vacation. "You just watch things more closely," he said. Americans are doing a lot of that these days, especially after Monday's attack on the Boston Marathon, where three people died and more than 180 were wounded when a pair of bombs exploded near the finish line:
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NEW: Police chief acknowledges "a bit of anxiety" on Capitol Hill
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Americans are looking over their shoulders after recent U.S. violence
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But the violence won't stop many from going out and living
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Events such as Monday's bombings remind us that "we're all vulnerable," professor says
The interest in the @placeholder terrorism case "will last for a few days and perhaps a week, and then it will become a distant memory for most people," he said.