32-year-old Erik Weihenmayer from Boulder, Colorado, became the first blind person to reach the summit of Mount Everest.
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Colorado became the birthplace of the cheeseburger.
Mike the Headless Chicken lost his head.
Mexican grill chain Chipotle opened its first restaurant.
15 die in the Columbine High School massacre.
Colorado became the second US state to give women the right to vote.