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    Physical therapist assistant Suzanne Finucane, right, helps Zac Vawter as he practices walking with an experimental "bionic" leg at the Rehabilitation Institute of Chicago, Thursday, Oct. 25, 2012 in Chicago. Vawter will put his bionic leg to the ultimate test Sunday, Nov. 4, when he attempts to climb 103 flights of stairs to the top of Chicago's Willis Tower, one of the world's tallest skyscrapers. If all goes well, he'll make history with the bionic leg's public debut. (AP Photo/Brian Kersey)

    Physical therapist assistant Suzanne Finucane, right, helps Zac Vawter as he practices walking with an experimental "bionic" leg at the Rehabilitation Institute of Chicago, Thursday, Oct. 25, 2012 in Chicago. Vawter will put his bionic leg to the ultimate test Sunday, Nov. 4, when he attempts to climb 103 flights of stairs to the top of Chicago's Willis Tower, one of the world's tallest skyscrapers. If all goes well, he'll make history with the bionic leg's public debut. (AP Photo/Brian Kersey)

    Man climbs Chicago skyscraper with bionic leg

    Zac Vawter became the first person ever to complete the task wearing the mind-controlled prosthetic limb, Sunday, Nov. 4, 2012 in Chicago. Vawter, who lost his right leg in a motorcycle accident, put the smart limb on public display for the first time during an annual stair-climbing charity event called 'SkyRise Chicago' hosted by the Rehabilitation Institute of Chicago, where he is receiving treatment.