The 108-story Sears Tower in Chicago is topped out at 1,451 feet (442 m) as the world's tallest building.

The Willis Tower, formerly and still commonly referred to as the Sears Tower, is a 110-story, 1,451-foot (442.3 m) skyscraper in the Loop community area of Chicago in Illinois, United States. Designed by architect Bruce Graham and engineer Fazlur Rahman Khan of Skidmore, Owings & Merrill (SOM), it opened in 1973 as the world's tallest building, a title that it held for nearly 25 years. It is the third-tallest building in the Western Hemisphere, as well as the 23rd-tallest in the world. Each year, more than 1.7 million people visit the Skydeck observation deck, the highest in the United States, making it one of Chicago's most popular tourist destinations.

This is a list of the tallest buildings. Tall buildings, such as skyscrapers, are intended here as enclosed structures with continuously occupiable floors and a height of at least 350 metres (1,150 ft). Such definition excludes non-building structures, such as towers.

May 4 is the 124th day of the year in the Gregorian calendar; 241 days remain until the end of the year.