Like Firehold Bravo but much larger diameter. I love this style, they are called indestructible for a reason.
These constitute serious design for long term survival in an atomic war. Most other designs are a poor replacement for really solid survivability and strength compared to this model. The radiation protection they afford in an increasingly radiation contaminated environment is excellent.
The design of the entryway is far superior to that of Firehold Bravo which I modelled after the experimental prototype from Oak Ridge Labs. I intend to remedy my mistakes next time around, particularly in terms of accessibility.
Notice the guy doing the tour could be my distant relative. Facial bone structure and general look is all Neanderthal. A coincidence to be sure. Pay attention to the fact that K-selected people are always talking about the safety of their kin relationships and their responsibilities to them whereas R-selected never seem to worry about their offspring or what becomes of them. For the two types of animals to try to have a conversation is nearly impossible because they have no shared context. Left-wing (Rs) are only interested in random sexual encounters and impulse gratification, not really possessing souls to reflect very deeply on any subject including the future.