Amputee Zac Vawter walked up 103 stairs in Chicago’s Willis Tower using the first operational mind-controlled robotic leg. Vawter completed the feat during SkyRise Chicago, a charity stair climbing event that benefits the lead developer of Vawter’s robotic prosthetic leg, Rehabilitation Institute of Chicago. Nerves leading to his amputated leg were reassigned to another muscle in a technique called Targeted Muscle Reinnervation. The prosthesis reads the redirected nerve impulses and translates them into movement with motors in the knee and ankle joints. The robotic leg is the product of an ongoing research project led by the Rehabilitation Institute of Chicago, in collaboration with Vanderbilt University, MIT, and other research partners, and funded by the Department of Defense.