
Willis Tower, since 1973 a brawny symbol of Chicago, is flexing its marketplace muscle, reasserting its relevance amid the changing nature of office work.
Blackstone, the tower’s owner, has made the 110-story building fit for a new era, spending $500 million to ensure it’s more hospitable to tenants and visitors alike. It involved a change in layouts and attitudes at a building that for decades was standoffish with its surroundings.