A prominent feature of Northwestern architecture is exposed heavy glue-lams or wooden beams supporting and shaping the roof and this project by Architects Bohlin Cywinski Jackson does not disappoint with its use of those architectural details. Its sweeping profile adds a gentle green character to the neighborhood. The columns and purloins feel a bit like a forest. The roof consists of 18,000 low water plantings which library patrons can check out up close through a rooftop “periscope” near the checkout desk. The green roof absorbs a tremendous amount of storm water in the rainy city, reducing stress on the city’s drains. The roof also helps maintain the temperature inside as well as adding some biodiversity to the neighborhood.