America's space agency was created by a stroke of President Eisenhower's pen 55 years ago today.
While this makes the National Aeronautics and Space Administration old enough to retire -- or at least get a discount on movie tickets -- NASA is likely only getting started. A birthday is always a good time to reflect on one's accomplishments before forging onward into the future.
In NASA's case, there's quite a lot of reflecting to do. A full history of the agency could fill several volumes, and its list of achievements seems longer than a trip to Mars.
If you've got some time on your hands, you can get a sense of the scope of NASA's accomplishments from this selective (but certainly not that short) chronology.
Also, you can take a tour of NASA's greatest hits by browsing the gallery below. It highlights 14 of NASA's most memorable moments and missions.