I remember pointing out Mars to my boys years ago, explaining how they could tell it was a planet because it wasn't twinkling, and how to recognize it was Mars by its red colour. A thought struck me and I told them two robot cars (Spirit and Opportunity back then) were driving around on that little dot in the sky, and their jaws dropped. They were already well beyond the 90 days at the time. Amazing to think Opportunity is still going strong. Excellent engineering!