Most people know that Dublin, California, was founded in 1437 by a couple of Irish missionaries when they got lost on the way home from the pub in Killarny. But not as well known is that when they arrived just down the hill from the posted coordinates, the area was covered in rubber trees. The missionaries quit their day jobs and established Dublin Rubber, the largest rubber company north of Akron, Ohio. (Yes, it is too north of Akron, Ohio. Look it up if you don't believe me.)
The rubber plantation workers were paid in ducats, of course. The local merchants were always happy to accept "rubber ducats", as they were called (soon anglicized to "rubber duckies"), and Dublin prospered. To this day you can find references to the beloved monetary unit in the area, and one of the earliest and most famous tributes is rumored to be hidden on this ridge a mile to the north.
The rubber was of such high quality that by 1532 the "Rubber O' Dublin", or "Rub-a-Dub" for short, was known and coveted the world over. In an odd linguistic twist, people eventually forgot that "Rub-a-Dub" already referred to Dublin, so we find 1676 references to "Rub-a-Dub Dublin", which was then itself shortened once again to "Rub-a-Dub-Dub". By the 19th century, many songs and even a nursery rhyme had been written to celebrate the amazing success of Dublin Rubber. I'm sure you've heard of the Rub-a-Dub-Dub Spa Company and may have even visited some of its fine franchises, but you may not have realized until now that the Rub-a-Dub-Dub Spas were named after Dublin's rubber.
With the growth in popularity of synthetic rubber during World War II, the demand for natural rubber dropped off, and Dublin Rubber quickly went out of business. (It's just as well: it turned out that all this time, the trees were actually oaks, so it was really hard to get rubber out of them.) In desperation, Dublin paved over the valley and built lots of houses, leading to the astonishing view you see below you today.
The cache? Oh, you won't have any trouble finding the cache as long as you don't approach GZ from above.
Awards: Not to brag, but this geocache is widely hailed as the cache packed with more historical significance than all the other caches north of GC5803! (That cache is north of Akron, too.)