May 3 - Sears Tower

Sears Tower in Chicago was topped out on May 3, 1973, at a height that surpassed New York’s One World Trade Center as the world's tallest building at that time. When the tower was planned in 1969, Sears, Roebuck & Co. was the world’s largest retailer, and it decided to consolidate all divisions in one place in Chicago. Begun in 1970, the tower is actually nine bundled square “tubes,” each essentially a separate building: two tubes are 50 floors high, two are 66 floors, three are 90 and two are 108. The design was inspired by an advertisement for a package of cigarettes. Sears occupied the lower half until, much diminished, it moved out in 1995. Now renamed Willis Tower, it remains the tallest building in the United States and the seventh-tallest freestanding structure in the world, behind Dubai’s Burj Khalifa and others. Its façade consists of 28 acres of black aluminum panels and more than 16,000 bronze-tinted windows. The tower's sway has been known to induce motion sickness in people working at the top.