CHICAGO (CBS) — Hundreds of people will be taking part in a charity climb to the top of the Willis Tower Sunday, but all eyes will be on one man.

WBBM Newsradio’s Bernie Tafoya reports 31-year-old Zac Vawter will be climbing the skyscraper’s 103 flights of stairs on a bionic leg.

The robotic limb is a first-of-its-kind prosthetic that responds to his thoughts. Vawter will think of what he wants the leg to do, and the electronic impulses will travel from his brain to his hamstring, triggering movement in the man-made leg.

The technology was developed in part by researchers at the Rehabilitation Institute of Chicago. The $8 million in research for the project came from the U.S. Department of Defense.

Vawter, a software engineer, lost the right leg he was born with in a motorcycle accident. On Sunday, he’ll be among 2,700 people taking part in “SkyRise Chicago,” the Rehabilitation Institute’s charity climb to the top of the Willis Tower.

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