Since moving to Japan in 2012, I have reported on the aftermath of the Fukushima nuclear disaster - speaking to experts, visiting the site and watching the clean-up. For the Editors, a programme which sets out to ask challenging questions, I consider what I have learned.
Firstly, Fukushima was not an unavoidable natural disaster. For many outside Japan it is easy to draw the conclusion that Fukushima is unique, as very few places experience such huge earthquakes and tsunamis as Japan. So, the logic goes, there are no real lessons to be learned for other countries.
Much the same was said after the Chernobyl nuclear disaster in Ukraine in 1986. Chernobyl was a bad design, a similar accident could not happen in Japan, which has Western-designed reactors. But it did.
Prof Kiyoshi Kurokawa chaired the Japanese parliamentary inquiry in to the Fukushima disaster and his conclusions are devastating. It was, he told me: "Man-made, and made in Japan."
Tatsujiro Suzuki, the deputy head of Japan's Atomic Energy Commission, has also been damning.
"There were studies which showed a one-in-1,000-year probability of the Fukushima coast being hit by a 10m tsunami," he said. "Unfortunately, those studies were dismissed. The nuclear industry didn't think it would happen, so they didn't prepare for it," he said.
For me, this is the most revealing and shocking part of the Fukushima story. When the earthquake and tsunami hit on 11 March 2011 there was no plan for how to deal with such a large and complex disaster. How was this allowed to happen?
Prof Kurokawa blames what he calls "regulatory capture", a process by which the nuclear power industry "captured" the bureaucracy that was supposed to regulate it.
Put crudely, the "poachers" and the "gamekeepers" were far too close. Many senior bureaucrats from Japan's Nuclear Industry Safety Agency would take lucrative jobs in the nuclear industry after leaving government.
The result was a nuclear industry imbued with a culture of arrogance, secrecy and complacency. Lessons learned after Chernobyl and Three Mile Island in the US were not implemented here. When disaster struck, Japan was woefully ill-prepared.