FYI. There's more to what's underground than just DUMBs and some tunnels and caves.
https://2012portal.blogspot.com/2018/01/operation-mjolnir.html
…The main faction making problems recently is the so-called Illuminati Breakaway Complex (IBC). IBC is a Chimera-controlled negative faction that broke away from the surface Illuminati network and went underground during the Archon invasion in 1996. They have created their own network of underground cities, connected with high speed trains. Their underground network is independent from US military underground network (constructed since 1950s and cleared by the Resistance after 2000), independent from the Chimera underground network (constructed 26,000 years ago and now almost completely cleared by the Resistance) and independent from Agartha underground network (created 26,000 years ago and expanded in the last few decades when the Resistance joined that network)…