Existential risks are risks that threaten the survival or long-term flourishing of humanity. Avoiding them is an obvious top priority. But if a major catastrophe was to occur, what could we do to prevent humanity from going extinct? Can we ensure that survivors can rebuild civilisation? Anders Sandberg is a senior research fellow at the Future of Humanity Institute at the Oxford Martin School at Oxford University. His research centres on management of low-probability high-impact risks, estimating the capabilities of future technologies, and very long-range futures. He has a background in computational neuroscience, transhumanism, and future studies. This talk was given at a TEDx event using the TED conference format but independently organized by a local community. Learn more at https://www.ted.com/tedx