It's An Underground Bunker Party! (Atlas)
Atlas has been making these long lasting survival shelters for a while now, and it's amazing how efficient an underground dwelling can be. These may not be your primary residence, but it can be.
Most of them have two entry ways in case one gets blocked. One can be a secret exit.
If you prepare any place nicely, you can hardly tell you're underground. These examples are great!
Check out the bunker party!