Two 260-ft tall buildings, sixteen and seventeen floors respectively, with two-story rooftop mechanical penthouse space. This air rights development sits atop a three-level below grade parking garage and the Massachusetts Turnpike (I-90) tunnel. 350 Summer (under construction) is 425,000 sf and is designed to accommodate 384,000 sf of laboratory/office space. 400 Summer is 625,000 sf and hosts 580,000 sf of laboratory and related office space. The complex includes ground level neighborhood retail space and the “Summer Steps,” an outdoor public gathering place between the towers providing pedestrian connectivity from Summer Street to Congress Street, and to Boston Harbor via the Harbor Way.