 Complete the following phrase:  The Garrison Church was an important place of Germanys changeful history. Johann Sebastian Bach, Alexander I of Russia, Napoleon and others visited the building. In addition, it served as burial site of Frederick William I and his son Frederick the Great. Potsdams first freely elected council members met in the Garrison Church, Lutheran and Reformed Protestants founded the Prussian Union of Churches in it, and classical concerts took place there. In Nazi Germany, the building was used for propaganda purposes; at the same time, many 