Short for the Advanced Research Projects Agency Network, ARPANet was completed in 1969, sending its first message from a computer at UCLA. The original goal of the project was to allow large research computers to work collaboratively over long physical distances on complex scientific computations. Despite many claims to the contrary, it was not built to coordinate missile silos to respond to a nuclear attack. The technology progressed, moved into civilian markets, and the Internet you know and love came to be many years later.
The coords for this cache are approximate, as GPS is a bit wonky-jumpy at this location. The cache is accessible from the sidewalk. Do not I repeat, do not, wander on the grounds of the State Department nearby. No cache is worth getting arrested over. It should be a fairly straightforward find. Take a moment to check out the nearby historical marker to learn more about ARPANet and the significance of this site. Oh, by the way, if you're wondering about the name of the cache, check this site out. Congratulations to unusualsuspect for FTF!!