Geocaching is clearly the cat's meow when it comes to locating things with your GPS unit, but on the other side of GPS treasure hunts is Benchmark hunting. Benchmarks are markers of various types placed by the National Geodetic Survey teams over the past 200 years or so. More and more benchmarks are being placed and logged by other organizations (both military and private), which opens up an entirely new facet of GPS treasure hunting.
Geocaching.com allows users to log Benchmarks in addition to geocaches, so I thought I'd go ahead and explore it a bit. Turns out it can be quite rewarding if you want to just enjoy the thrill of the hunt and/or there aren't all that many caches in your area. I nabbed my first one about 3 days ago, and today on a short drive from Los Angeles County to Ventura, I grabbed 9 more.
Here's a sample of what a typical geodetical survey disk might look like: