pipe organs are installed in churches, synagogues, concert halls, schools, other public buildings and in private properties. they are used in the performance of classical music, sacred music, secular music, and popular music. in the early 20th century, pipe organs were installed in theaters to accompany the screening of films during the silent movie era; in municipal auditoria, where orchestral transcriptions were popular; and in the homes of the wealthy. the beginning of the 21st century has seen a resurgence in installations in concert halls. the organ boasts a substantial repertoire, which spans over 500 years.