When you dare to be powerful, to use your strength in the service of others, then it becomes less and less important whether you are afraid. May you be blessed with bravery that serves others well and serves you too.

Hugh Herr is building the next generation of bionic limbs, robotic prosthetics inspired by nature's own designs. Herr lost both legs in a climbing accident 30 years ago; now, as the head of the MIT Media Lab’s Biomechatronics group, he shows his incredible technology in a talk that's both technical and deeply personal — with the help of ballroom dancer Adrianne Haslet-Davis, who lost her left leg in the 2013 Boston Marathon bombing, and performs again for the first time on the TED stage...WATCH NOW