Although the Sears tower is one of the hardest building I have climbed in my entire life i do realize now that before Alex Honnold did climb freesolo Taipei 101 climbing a building hasn't been taken very seriously by the climbing community altough such a building as the Sears tower are 9 on a scale of difficulties from 1 to 10 i have created few years ago. With 200 buildings freesolo i have quickly understood that the system we were using on rocks couldn't apply with buildings. Disclaimer: im a