In the summer of 1947, a small space ship crashed near Roswell. Although it has long been thought that none of the alien visitors survived, apparently at least one managed to leave his (or her) mark by placing several caches in a unique formation.
Luckily, that unique formation is on BLM land, so there's no danger of anything disturbing the caches other than a stray cow or horse. Unluckily, the folks at the BLM office require that visitors to the site drive only on the dirt roads - which means in order to access all the caches a little walking is required (unless you happen to have a geo-spaceship and can cruise between caches). The total distance around the perimeter of the formation is just over 3 miles, with another 1.8 miles around those classic eyes. Although the terrain rating is a "2", because of the distance, it's a fairly easy walk on level ground.
PLEASE do not drive off the road(s) and do watch out for the usual desert flora and fauna. We're pretty sure there's a very large colony of badgers in residence as we discovered dozens and dozens of holes leading to their lairs. Or, maybe aliens live in those holes......
We spotted lots of Pecos Diamonds (mostly clusters) throughout the formation so be on the lookout, particularly in the northernmost area.
Many thanks to BLMbilbo for his assistance in finding the location.