The tallest building in America is getting a new name. Chicago's Sears Tower will be renamed Willis Tower after London-based Willis Group Holdings. The insurance broker announced the name change and other details of its agreement with the building's owners Thursday. “It just doesn't work,” said Robin O'Sullivan, a tourist from Cork, Ireland, as he walked into the Sears Tower's Skydeck entrance on Thursday. “It's known worldwide. Everyone in Ireland knows it's the Sears Tower.” It's all part of a deal with the London-based Willis Group Holdings. Along with moving 500 employees into 140,000 square feet (13,000 square meters) on multiple floors of the 110-story building this summer, the Willis Group gets the naming rights as part of its lease agreement with the real estate investment group that owns Sears Tower. The name change isn't the first in recent years for Chicago. In 2006, the city's State Street shopping district saw Marshall Field's department store become Macy's and in 2003 the White Sox started playing baseball at US Cellular Field instead of Comiskey Park. “We certainly appreciate and understand the sentimental attraction to the Sears Tower name, and it's certainly a Chicago icon,” said Will Thoretz, a spokesman in New York for Willis Holdings Group. “Our move into Chicago is a good thing for the city. We're bringing hundreds of jobs into the city.” The company requested the change and isn't paying extra for naming rights to the tower, Thoretz said. Willis is moving six local offices into the building. The question, though, is if people will popularly refer to the building as anything other than the Sears Tower, said Tim Samuelson, the city of Chicago's cultural historian.