Take a breath and be brave. Very, very brave.... smile....Behold the "Willis Tower" in Chicago (formerly the Sears Tower) - the tallest building in North America and its famous attraction, The Skydeck. In January 2009, the Willis Tower owners began a major renovation of the Skydeck, to include the installation of glass balconies, extending approximately four feet over Wacker Drive from the 103rd floor. The all-glass boxes allow visitors to look directly through the floor to the street 1,353 feet (412 m) below. The boxes, which can bear five short tons of weight (about 4.5 metric tons), opened to the public on July 2, 2009.