Gary Brierley: Underground space hits almost every line on the CSO’s wish list. It can be made nearly invisible from the surface, provides very tight access (and egress) control. Underground space provides much better protection from earthquakes. Maintenance requirements are lower, which means fewer maintenance workers to pay. Nobody will be on your back about a facility that is 200 feet underground, he says. Put a structure under the surface and the neighbors will forget about it, surely the happiest possible outcome from a security point of view.”]