The Sun-Times broke the story that, after much deliberation, Mayor Richard M. Daley has decided not to run for reelection. Daley has been in office since 1989, so his impact has been vast, especially on the city’s built environment. From planting thousands of trees and promoting green roofs and LEED construction, to building magaprojects like Millenium Park and championing development like the new Trump Tower, Daley’s vision shaped the architecture and urbanism Chicago, as well as the city’s identity, arguably more directly than any other mayor in the country. With less than six months before the election, those interested in replacing Daley will have to work fast. President Obama’s Chief of Staff, Rahm Emanuel, generated considerable buzz earlier in the year when he said he’d like to be mayor someday. He quickly qualified that he would not challenged Daley. No word yet on his intentions following Daley’s announcement. While Emanuel is known to be a strong armed character, his views on design and the built environment are unclear at the point. Whoever becomes mayor, Daley’s shadow will be a long one.