https://www.answers.com/stadiums/Was_there_problems_building_the_Willis_tower
Was there problems building the Willis tower? - Answers
Yes, the construction of the Willis Tower (originally known as the Sears Tower) faced several challenges, including design disputes, engineering complexities,...
the willis towerproblemsbuildinganswers
https://www.fox32chicago.com/video/1215529
The Willis Tower celebrates its 50th birthday | FOX 32 Chicago
The Willis Tower turned 50 on Wednesday.
the willis tower50th birthdayfox 32celebrateschicago