Oh, what beautiful organ music, passing by the cathedral in the wee hours of the morn....

"The Toccata and Fugue in D minor, BWV 565, is a piece of organ music composed by Johann Sebastian Bach sometime between 1703 and 1707. It is one of the most famous works in the organ repertoire, and has been used in a variety of popular media ranging from film, to video games, to rock music, and ringtones. The attribution of the piece to Bach has been challenged since the early 1980s by a number of scholars, and remains a controversial topic"

From WickipediA