Also possibly of interest, the largest MANUAL (completely mechanical, with no electricity used in any parts, including the bellows) organ in the world is in the Holy Trinity Cathedral in Liepaja, Latvia. The initial build was finished in 1779, with further registers added in the late 19th century, and rehab work over the past ten years.

An excerpt of J.S. Bach Prelude & Fugue in A-min (BWV-543) played on the organ (excuse the poor quality, I think it was taken by a tourist):

I don’t know about you guys, but nothing gives me more musical chills down the spine than hearing what is arguably the most magnificent musical composition in human history (rivaled only by Bach’s Passacaglia and Fugue in C-min, BWV-582) being played on a period instrument; there’s a genuinely timeless spiritual aspect that transcends multiple human generations and historical eras, and when listening you feel a kinship and immediate connection to a time and era that is otherwise rendered alien and mysterious by the passing of the centuries.