The Salt Lake Tabernacle held the North American record for the widest unsupported interior space at its completion in 1867. Finished two years before the arrival of the railroad, it was constructed primarily of local stone, timber, and adobe. One of a long succession of buildings constructed to permit members of the Mormon faith to hear from their prophet, the Tabernacle accommodated over 13,000 people. A recent seismic upgrade provided a unique opportunity to view details of the historic building. Construction challenges, acoustics, the development of the organ, and subsequent alterations and upgrades are amply illustrated, providing a complete story of this magnificent edifice.