On September 5, 1977 NASA launched the probe Voyager 1, meant to study the outer Solar System. It reached Jupiter in 1979, then Saturn the next year. At this point the mission was supposed to end, but it was extended, and Voyager 1 kept flying away and away. In 2012, after 35 years of activity, Voyager 1 entered the interstellar medium.
Voyager 1 journey is an amazing achievement for Science, but it's also just awesome thinking about this human artifact that's boldly going where no man (made objects) has gone before.
But Voyager 1 doesn't cease to create wonder, because just a few days ago, after 40 years since the launch, NASA gave the spacecraft the order to fire up its thrusters, and they worked! After being unused for 37 years! Isn't is astonishing?!? :D