In May 2008, I placed a Multi-Cache along Skyway Drive trail, just outside the Helena Regional Airport. GC18EWR The Solar System Series was a scale model of the Solar system, and its purpose was to give geocachers a sense of the size and scale of our Solar system. Starting at the posted coordinates, the geocacher would "follow" the route of the New Horizons spacecraft, which at the time, was on a mission to conduct close fly-bys and capture detailed photographs of the surfaces of both Neptune and Pluto.
Using plastic cattle ear-tags and 10" fence-rail spikes, I marked out the scale model and submitted the geocache to the reviewer. Once published, this Multicache was found often and well received. I had also included a special Mystery Cache, GC18F71 Where Is "Planet X"? that could only be found if the geocacher had collected all ten of the numbers written on the back of each marker. This was long before Bonus Caches existed, but people really liked the idea of being able to get this geocache only if they completed the Multicache.
Unfortunately, like many of my other earlier placed geocaches, once I moved out of the area, I had to archive this one. As it turned out, a large box store was built right on top of the previous geocache location, so I suppose I would have had to remove the geocache anyway.
Today, however, after having replaced both of these geocaches, and using more durable materials, they have been published and ready to be found. GCAXWNN Helena's Copernican SystemCAXWNN Helena's Copernican System and GCAXWPD New Horizons' Discovery: Where Is "Planet X"? are redux geocaches of my previous two and I am hoping that they will be as well received as the originals.