This elegant Renaissance and Baroque Revival structure, San Francisco's second-oldest hotel, fronts the entire west side of Union Square. Commissioned by millionaire Charles Crocker, it opened in 1904 as the Hotel St. Francis. After the 1906 fire, the architectural firm Bliss & Faville rebuilt and enlarged the hotel, which had previously occupied only half the block; it resumed business in 1907. In the decades since, celebrities and dignitaries including Queen Elizabeth II, the Shah of Iran, and all US presidents since Taft have favored the St. Francis for its sumptuous interior, central location and emphasis on service. Step inside to ogle the entrance hall, with its coffered ceilings, travertine marble and ornate balconies. The Magneta grandfather clock has long been a favorite rendezvous point for city socialite.A 32-story tower was added to the rear of the hotel in 1972. Visitors who brave the vertiginous ride up in its glass exterior elevators are rewarded with expansive views of Union Square, the Financial District and the Bay Bridge.