 The completion of the Central Artery Project (The Big Dig), with its expansive necklace of greenspace, the Rose Kennedy Greenway, gardens, and public space, has made these now historic apartment buildings central characters in the most costly urban improvement project in US history at the time.Over the decades, the towers have required major renovations, including the replacement of all the windows with high-end double-pane windows, as well as replacement of the electrical and HVAC systems.Severe corrosion of the heating and cooling water pipes led to them being replaced by copper pipes in 2009.