Although this Nob Hill cathedral, designed by architect Lewis P. Hobart, appears to be made of stone, it is in fact constructed of reinforced concrete, beaten to achieve a stonelike effect. Construction began on the site of the Crocker mansion in 1928 but was not completed until 1964. Among the more interesting features of the building are its stained-glass windows, particularly those by the French Loire studios, depicting such modern figures as Thurgood Marshall, Robert Frost, and Albert Einstein; the replicas of Ghiberti's bronze Doors of Paradise at the east end; the series of religious frescoes completed in the 1940s by Polish artist John de Rosen; and the 44-bell carillon. Along with its magical ambience, Grace lifts spirits with services, musical performances, and its weekly Forum (Sun 9:30-10:30am except summer and major holidays), where guests lead discussions about spirituality in modern times.