…that the organ in the Cathedral St. Stephan is the largest cathedral organ in the world?

It is in actual five organs: the Main organ, the Gospel organ, the Epistel organ, the Echo organ, the Choir organ. They can be played separately or together from the main console as they are joined with 120 km of electric cable. The sound of the Echo organ which is in the attic comes through the so called Holy Ghost opening.

There are 17.974 pipes, 233 registers and 4 glockenspiels. The longest pipe has a length of 11 meters and the shortest of 6 millimeters.

The organ is also among the largest organs in the world the most played, concerts being given 6 days the week at noon from May through October.