Symphony Hall opened on October 15, 1900. It was the first concert hall designed with acoustical principles in mind and is regarded as one of the two or three finest halls in the world. With the exception of the wooden floors, the Hall is built of brick, steel, and plaster, with only a moderate amount of decoration. The walls of the stage slope inward to help focus the sound. The side balconies are shallow so as not to trap any of the sound, and the recesses of the coffered ceiling, along with the statue-filled niches along the three sides, help to distribute the sound throughout the hall. The 16 replicas of Greek and Roman statues are related in some way to music, art, or literature. They were placed in the niches as part of an appreciation of the frequently quoted words, "Boston, the Athens of America," written by Bostonian William Tudor in the early 19th century. The Symphony Hall organ, an Aeolian Skinner designed by G. Donald Harrison and installed in 1949, is considered one of the finest concert hall organs in the world.