Situated on a hillside inside the Presidio, the 100-foot-tall structure composed of cypress tree trunks dwarfs the young pines surrounding it, and towers over the rows of cypresses to the west. Completed in 2008, Spire is built of unhealthy trees that required cutting, and at first glance looks like the first step in prepping the city's best-ever bonfire. Pass it at different times of the day and year, and its subtle beauty becomes more apparent: The spire cuts a sliver out of the fading daylight, and its pinnacle reaches out and up like someone on her tiptoes, grazing the low-lying fog — or like that Transamerica tower. For the most part unvisited by tourists, this impressive steeple just sits on the hillside a subtle, natural mirror to the building that dominates the downtown skyline.