18. This Jan. 25 2012 photo shows retired Sen. John Glenn at his office in Columbus, Ohio. It’s been 50 years since his milestone spaceflight in a Mercury capsule, and almost 14 years since his space shuttle flight and retirement from the Senate. “I’ve been very fortunate to have a lot of great experiences in my life, and I’m thankful for them,” he says.

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Jay LaPrete / AP