Escaping underground: the eerie new age of bushfire bunkers — With concrete walls, flame-proof doors and wine racks, bushfire bunkers offer the promise of safety, at least for those who can afford …::With concrete walls, flame-proof doors and wine racks, bushfire bunkers offer the promise of safety - at least for those who can afford them
These are similar to tornado shelters in the US. Several of my neighbors have them.
They even make some that are basically a porch and steps with a hatch to open and climb in.
They are also common with cheap housing like trailer houses.