Dominating Avalon from a point on the bay's northwestern end is Catalina's most prominent architectural landmark, a 140ft-tall circular Art Deco building (1928-29) with Spanish and Moorish flourishes. Built as a tourist attraction by William Wrigley Jr., the casino enjoyed its heyday in the 1930s and 1940s, when dancing enthusiasts flocked to its ornate ballroom for entertainment by such big-band legends as Benny Goodman, Kay Kyser and Freddy Martin. Music from the casino was broadcast live on the radio throughout the US. Despite its name, gambling was never permitted here.Walking tours depart from the box-office loggia, decorated with Art Deco undersea murals by John Gabriel Beckman. Additional Beckman murals depicting Southern California history and scenery adorn the walls of the 1,184-seat Avalon Theatre, which now screens first-run feature films. The theater boasts a full-scale pipe organ and an elliptical ceiling covered with 60,000 squares of silver leaf. The ornate Avalon Ballroom, still a dance venue, features the world's largest circular dance floor-an open, cantilever-supported 10,000sq-ft surface of cushioned maple, white oak and rosewood. Facing the bay on the casino's lowest level, a small museum presents exhibits on Catalina's history, natural history and archaeology (open Apr-Dec daily 10am-4pm; rest of the year Fri-Wed 10am-4pm; $4; 310-510-2414).