Total Necessity.

Two hundred years ago I would have looked at this question and answered with a firm and unwavering 'A Home'.

However, this is the space year 2014! We have long since passed the magical year of 2001 when a space Odyssey sort of predicted where we would be by that very year. We have nailed 2001 - it is now antiquated.

These days, the most important thing a human can have besides food, water and family is largely dependent on where you live.

If I lived in China, I would say friends in high places.

If I lived in Ukraine I would say a panic room.

If I lived in Afghanistan I would say a large and well equipped Brigade.

However, I live in England, so I would have to say........MONEY. And plenty of it.