A fifth worker died after falling from the tower in an unrelated incident four days later. Work was halted again that June due to a labor strike, and Sears began moving furniture into the building that month. The construction cost was about US$150 million, equivalent to $ million in dollars. Despite the size of the project, Sears executives said the building could not accommodate Sears' annual shareholder meetings, and the company continued to rent space in other structures. 20th century Opening and early years The first Sears employees began moving into the tower during the weekend of September 9, 1973. Flashing beacons on the building's roof, the first to be installed at any building in Chicago, were activated the same month. Upon the tower's opening, broadcasters at the John Hancock Center, Chicago's second-tallest building, had to decide whether to relocate to the Sears Tower. Two television stations decided to relocate. Six other stations remained at the John Hancock Center, citing a study which showed that relocating to the Sears Tower would provide only minimal benefits. Documents released in late 1973 indicated that the Sears Tower would cause much more interference than either Sears or the television stations had disclosed. WLS-TV moved to the Sears Tower in February 1974, followed by WTTW the next month. By March 1974, three-fourths of the space in the building was occupied; Sears had leased the upper stories to tenants such as Goldman Sachs, Northwest Industries, and Schiff Hardin. A mobile sculpture by Alexander Calder was dedicated in the lobby in October 1974. Sears' optimistic growth projections were not realized; instead, in late 1974, the company fired 500 workers, about seven percent of the 7,000 Sears employees that worked in the tower. Competition beyond its traditional rivals such as Montgomery Ward arose from emerging retail giants including Kmart, Kohl's, and Walmart. As a result of a surplus of office space that emerged in the 1980s, the tower did not draw as many tenants as projected and so stood half-vacant for a decade. Renovation and relocation In February 1984, Sears announced that it would renovate the building to attract visitors to the lower floors. At the time, 6,500 Sears employees occupied more than half of the building, taking up the lowest 48 stories. The remainder of the tower was occupied by 5,500 employees from about 70 companies. As part of the project, the main entrance was covered