Whether caused by human error or by nature, the world's worst disasters are not easily forgotten. Emotive images beamed around the world of the destruction caused by the Loma Prieta earthquake in 1989 or the Chernobyl nuclear accident still resonate today. Yet, out of the devastation, uplifting stories of heroism, self-sacrifice and improbable survival have emerged. Told from the point-of-view of survivors and rescuers, this compelling series reveals the truth behind seven iconic disasters, bringing their stories vividly to life. Each episode considers whether the disaster could have been prevented and the important lessons learnt to avoid future large-scale catastrophes.