Professional ballroom dancer Adrianne Haslet-Davis lost her natural ability to dance when her left leg was amputated below the knee following the Boston Marathon bombings in April 2013. Hugh Herr was introduced to Adrianne while meeting with bombing survivors at Boston's Spaulding Rehabilitation Hospital. For Professor Herr, this meeting generated a research challenge: build Adrianne a bionic ankle prosthesis, and restore her ability to dance. The research team for this project spent some 200 days studying the biomechanics of dancing and designing the bionic technology based on their investigations. The control system for Adrianne was implemented on a customized BiOM bionic ankle prosthesis.