San Francisco, as viewed from Twin Peaks. Photo by Flickr user Andrew Mace. Deborah Cullinan is CEO of Yerba Buena Center for the Arts in San Francisco. This month leaders from several Knight communities will visit us here in San Francisco as we explore the future of the main artery of our city. Laid out 150 years ago, Market Street spans three miles from the waterfront to the hills of Twin Peaks. It has history and purpose. It also faces serious challenges, and we see an opportunity for other cities to learn from our experimentation. Market Street has carried horse-driven streetcars, trolleybuses and cable cars; it has hosted parades and celebrations marking worldwide events; and, every day, it carries thousands of pedestrians, transit riders, skateboarders and cyclists. Yet, its wide sidewalks, busy transit centers and distinct neighborhoods aren’t working to create inspiration and connection.