The dramatic new building is situated on a stubbornly bleak stretch of Mission Street. Designed by Thom Mayne, of the L.A. firm Morphosis, this is probably the most visible symbol of the new San Francisco. The Federal Building is only 18 stories tall, but is located in an otherwise low-rise part of town, so you can see its asymmetrical silhouette, and the sunshade that looks like an insect's exoskeleton, from all over town. At night the Federal Building is illuminated by a James Turrell sculpture, a line of LED's that starts on the plaza level and traces the contours of its "sky garden." Like many LEED-certified buildings, this one features natural ventilation and has windows that open automatically according to climate conditions. The hallways and most surfaces are coll gray concrete made with 50 percent recycled slag. A series of Ed Ruscha murals was commissioned for the elevator lobbies. The building gives the impression that our federal government is an immensely chic organization.