shigeharu aoyama captured these scenes with his camera. (speaking japanese) >> o'brien: aoyama documented teams of workers wearing hot, uncomfortable protective gear, navigating a labyrinth of air locks, struggling to clean up a huge radioactive mess. he then ventured outside to the destroyed reactors themselves. >> o'brien: is that you? >> yes. >> o'brien: his rarely seen footage, which he shared with frontlinis the most complete record of life inside the plant shortly after the accident. >> this is truly first case of an entrance of that site i play. >> o'brien: wow. (speaking japanese) >> o'brien: his stark footage shows the massive damage caused by the explosions. >> o'brien: aoyama photographed the apocalyptic tsunami damage on the plant's ocean side, where the emergency generators and seawater pumps had been. >> o'brien: here and all around the world, nuclear experts were troubled by a vexing question-- how could this happen in japan, a country so well known for its technological and engineering brilliance? (speaking japanese) >> o'b