Against all odds, the old Main Post Office in the heart of downtown Chicago has been brought back to life after sitting idle for over two decades. Filled with antiquated mail-sorting machines and haunted by the ghosts of old postal workers, it was gutted and reopened in 2019 as the home of Walgreens and several other businesses. The historic landmark built in the 1920s is now crowned by a 3.5-acre rooftop park that includes walkways through fields of native perennial plants and grasses.