There are many ways in which to prepare a BOL, this would include but isn't limited to building an underground bunker, walls, setting up security cameras, motion sensors, water well...etc. In terms of location you could choose somewhere remote, more modern, in a warm climate, cold climate, dry, wet...etc. This list goes on and on. However, it is all dependent on what scenario you are prepping for. So, my question to everyone here is what do you consider to be the most important/must have features to a BOL? Maybe you want a large building in the woods somewhere that would be impervious to attackers. But, if the scenario is, say, a foreign invasion, it may be a better idea to have a bunker as opposed to a large house that is good for defense. Going undetected would be better than physical barriers for protection. This is just a thought to get the ball rolling, but please feel free to share you thoughts and let us all know what you feel would be the most important aspect to a BOL.