The legacy of the early oil barons and a $1 million-a-month construction boom in the 1920s can be seen on a walking tour of the historic central business district. Only New York and Miami Beach claim more Art Deco buildings. The 1927 Philtower Building, with its green-and-red tiled roof, monogrammed door knobs, brass elevator doors and 25ft vaulted ceilings, was once the tallest building in Oklahoma. It is linked by an underground tunnel to the 1930 Philcade Building, whose flamboyant Zigzag Style conceals carved-stone birds, reptiles and mammals in the terra-cotta foliage above its ground-floor windows. The Deco style employed by the Public Works Administration in the Depression Era represented a transition from Zigzag to Streamline. Perhaps Tulsa's finest example is the 1931 Tulsa Union Depot, now an office complex.