Built as and still commonly referred to as Sears Tower, the Willis Tower surpassed the World Trade Centre as the tallest building in the world, holding on to that title for 25 years. Today, it towers over the Chicago skyline, its obsidian-coloured glass exterior glinting in the sunlight. With its stark clean lines and minimalistic structure, the Willis Tower is an architectural triumph and work of art. While it is still a functional office building, the Willis Tower’s Chicago Skydeck is open to the viewing public for all who wish to catch a glimpse of the magnificent cityscape spread out below you. The Skydeck also offers an extra ‘Ledge’, which is a balcony constructed entirely out of glass (including the floor!) that extends from the 103rd floor of the Willis Tower. On a windy day, you can even experience how the tower sways, adding a new dimension to your experience.