This is an excellent performance, recording and video of Bach's epic Passicaglia and Fugue in C minor. Hans-Andre Stamme is the Organist, performing on the Trost Organ in Waltershausen.

You don't need to understand what a passicaglia or fugue are to enjoy this brilliant work, but in case you are curious, here is a brief definition.

A passicaglia is a baroque form characterized by a single repeating musical subject - usually in the bass - that is threaded into the fabric of the entire piece. It's kind of a musical game for composers, where you try to create as much variety and fluidity as possible while retaining a single melody within the piece at all times. This is probably the best and most well known passicaglia in existence.

A fugue is a baroque form that uses one short melody - or subject - as the basis for the entire piece, allowing for as much variation or manipulation of the subject as the composer pleases.

In this piece the fugal subject is taken directly from the Passicaglia subject.