A 31-year-old amputee has made history, becoming the first person to climb 103 floors of one of the world's tallest skyscrapers with a bionic leg.
Zac Vawter was wearing a prosthetic leg controlled by his mind on Sunday (local time) when he participated in ''SkyRise Chicago''.
The charity event raises funds for the Rehabilitation Institute of Chicago.
The event marked the bionic leg's first test in the public eye.
As Vawter thought about climbing stairs, the motors, chains and belts in his leg synchronised the movements of its ankle and knee.
Researchers cheered him on and noted the smart leg's performance.Institute officials say the leg and its climber held up ''fantastically''.
Vawter finished the climb in about 45 minutes.