Outdoor ice rinks and snowflakes in San Francisco are a sure sign that the holidays are officially underway. Skaters can take to the ice beginning Nov. 12 at Union Square and the Embarcadero Center and on Nov. 24 at the San Francisco Zoo; for an indoor warm up there's Yerba Buena. Market Street's Path of Gold will morph into a winter wonderland when giant LED snowflakes light up the shopping district from Second to Fifth Streets. The lighting ceremony will be held on Nov. 18. And it's all aboard at the Conservatory of Flowers. The Golden Gate Express, a miniature railroad winding its way through a magical holiday landscape of flowers and pint-sized San Francisco landmarks, starts its journey Nov. 20.