Chicago became home to the world's tallest building in 1973 when the Sears Tower was topped off. The Sears Tower is the tallest building in North America. The height to the top of the roof is 1,450 feet and the height to the highest occupied floor is 1,431. Sitting on two city blocks and rising one quarter mile (1,454 feet) above the ground, the Tower's 110 stories comprise some 4.5 million gross square feet of office and commercial space. Our bus tour guide, Rosette, allowed us a brief stop at the building to take a picture. She provided the perfect place to capture almost all of the building from across the street, yet it looks as if I was standing at the base of the building. Sears Tower has become the destination for millions of world tourists and a daily center of work and commerce for thousands of Chicagoans. Sears Tower has also served as a frequent backdrop to numerous groundbreaking films from Ferris Bueller's Day Off (1986) to The Fugitive (1993), it has been scaled by such daring acrobats as Spider Dan (1981) and Alain "Spiderman" Robert (1998), it has been a highlight of media controversy in response to the CTBUH (1997), it has been a center of preparations for making Chicago HDTV capable (2000), and most recently Sears Tower has been placed on the city's list of focal points for protecting against terrorism (2003).