Lots of people share their craft with their son or daughter in an attempt to pass on their legacy and the skill that they practice.
However, not many pass on the trade of building bunkers for infamous public enemies. Such appears to be the legacy of the woman who designed Adolf Hitler's bunker.Two generations later, her grandson would go on to be the designer of Saddam Hussein's bunker.
One can only guess how a family gets in such a business, but there is no guesswork in regards to why the grandson was asked to build the bunker. Simply put: He was good at his job. Massive bombs created for the purpose of reaching and tearing apart underground bunkers were unable to even scratch the man's creation.
Layers of concrete in its construction were put in place above the bunker for the purpose of 'tricking' any bunker busting bombs that 'detect' the amount of levels or floors that it crashes through before it explodes. The palace above the bunker was almost completely mutilated by the explosions, showing just how defensible the designer's layout turned out to be.