What really happened in Fukushima: Did we learn from the disaster?

We all remember the disaster in Fukushima. The questions are: What happened really there? and What did we learn from it? Nuclear power has long been touted as the energy saviour in terms of environmental impact and capacity generation. The incident at Chernobyl nearly 30 years ago cast huge doubts over the safety - and wisdom - of relying on nuclear power too heavily. The recent Fukushima disaster raised the spectre of nuclear safety and the possibly horrendous fallout and consequences from a major nuclear accident for the world to consider and worry about all over again.