DARPA Requires Tunnels

The US Defence Advanced Research Projects Agency has put out a public buyers advertisement, which itself is unusual for a governmental organization regardless of the circumstances. In this case it is even stranger because what they are asking for is underground tunnels. They Tweeted the following: "Attention, city dwellers! We're interested in identifying university-owned or commercially managed underground urban tunnels and facilities able to host research and experimentation... It's short notice. We're asking for responses by Aug. 30 at 5:00 PM ET." There is a link in the Tweet that takes you to this page where the request is made more formally: https://www.fbo.gov/index?s=opportunity&mode=form&id=8260d35188c377a0be5bf2ef1ee5ed41&tab=core&_cview=0. There is a PDF sharing link for the document giving further details which is simply called DARPA-SN-19-75. It explains how the subterranean domain has become relevant for global security and search-and-rescue missions. It then continues with this very ominous sentence: "DARPA is interested in understanding the state-of-the-art in innovative technologies that may enable future solutions to rapidly map, navigate, and search unknown complex subterranean environments to locate objects of interest." Source: https://www.livescience.com/darpa-weird-tunnel-tweet.html. What on earth does it mean by "unknown complex subterranean environments" and "objects of interest"? What "object of interest" can be found in an underground tunnel that would be the concern of DARPA? As far as I can tell such motivations would only interest an archaeologist or potholer. The document then describes how the agency is seeking locations where they can carry out research, conduct "experiments"... what kind!?... and develop technology for this activity. They specify that the areas must be closed off to the general public. Whatever DARPA has planned then it's probably bad news for the free people of the world. It is clear that the government want control of underground spaces in the same way they want control of space and the internet. There are genuine secrets below our feet in the same way that there are above our heads. These are enigmas connected to cryptozoology, UFOlogy and ancient mysteries; see background links below for details. The government cover these things up in the open air and space. Of course they will want to cover them up in the dark places below the earth's surface too.

See here for background: https://hpanwo-voice.blogspot.com/2013/12/mysterious-object-in-seattle-tunnel-dig.html.

And: https://hpanwo-voice.blogspot.com/2017/06/swiss-tunnel-opening-ceremony.html.

And: https://hpanwo-voice.blogspot.com/2017/04/strange-underground-noises-in-derby.html.

And: https://hpanwo-voice.blogspot.com/2016/10/monster-in-sewer.html.