The story of Prince Charles and Diana’s whirlwind romance seemed like a fairytale come to life – at least it did at first. Behind the scenes, things were very, very different. It took us a while to find out, but it seems Charles and Diana’s marriage might have been doomed not long after it started. And the origins of that breakdown might be pinpointed to a single event – and one very bad joke by Prince Charles made at Diana’s expense.