SAN FRANCISCO (AP).- The city on Monday launched a yearlong 75th anniversary celebration of the opening of the iconic Golden Gate Bridge with a string of parties, guided tours and festivals to be held along the waterfront graced by the burnt-orange span since 1937. “The Golden Gate Bridge stands today as a testament of innovation and imagination, a bridge built by the people during the Great Depression,” said Janet Reilly, president of the bridge district board. She and dozens of other civic leaders, national parks officials, bridge authorities and supporters spoke before a backdrop of the bridge set against a crisp, blue winter sky. Authorities, however, won’t be inviting the public to walk en mass along the storied bridge that marks the opening to San Francisco Bay. Officials tried that in 1987 for the 50th anniversary. They closed down the