To understand E=mc2 it helps to go back to the year 1904. Albert Einstein was then an unknown 25-year-old, who had offended his professors at university so much because of his lack of obedience that they had refused to write him letters of recommendation to get a good job. He had ended up as a patent clerk in Bern, Switzerland, where the town's one science library was closed on his day off, so he couldn't keep up with the latest research.

When he did try to work on his own ideas at the office, he had to stop whenever his supervisor got close, and slam his notes into a drawer - which he jokingly called his "department of theoretical physics" - so no one would see. And that was the ideal preparation for what he was about to achieve.