707 West Genesee Avenue (850 South) in Salt Lake.

rachels_slc_history has a great post about this place:
On Oct 28 1975, Claude “Corky” Nowell (later changed his name to Summum Bonum Amon Ra) had an encounter with intelligent beings from another universe.

Soon after, Corky founded Summum a church as defined by the government and a philosophy as described by Corky. Sum meaning Total, Mum meaning Mother Nature, and thus Summum meaning Totality of Nature.

Corky purchased a house at 707 W Genesee Ave (850 S) in SLC and built the first Summum Pyramid in his backyard. The second (and current) Pyramid was completed in 1979 and resurfaced in 2018.

Summum is known for several reasons: 1) establishing Utah’s first legal winery since Brigham Young; 2) going to the US Supreme Court over religious monuments; and 3) pioneering modern mummification.

Corky developed the mummification process in 1980 after experimenting on dead animals and human cadavers obtained from a medical school.

The first human to be mummified using the modern Summum techniques was Corky who died in 2008. His mummy is currently within the Summum pyramid.

Summum mummification aims to preserve the body by depriving it of oxygen through use of chemicals and multiple sealed layers.

Mummification is quite expensive and those individuals who have signed up for the service utilize life insurance policies that are payable to Summum upon death. Summum employs licensed funeral directors. A mausoleum was constructed in 2005.