He boldly went where no man had gone before.
Edwin White was the first human to step out in space 50 years ago today. Before that we were terrestrial creatures, after, we were space-farers. You might not be able to beat that, event the first walk on the moon doesn't quite top it.
One must really have a desire to explore and seek out in order to step out in the vacuum of space and 'test' the theory.
When told to come back in he said "Its the saddest moment of my life."