The crypt inside the Old Santa Barbara Mission is undergoing retrofit work this week.
Monday morning, crews opened the burial site for the first time.
The crypt is the only one built in a California Mission, and News Channel 3 got a rare look inside.
Some of the notable people buried inside are Gov. Jose Figueroa and members of the De La Guerra family, in addition to early pastors and famous missionaries.
"I don't think most people realize how much is down there. There is an anteroom, an arched hallway, and it opens up into a small room with burials in the walls, and built-in crucifix in the wall," explained Museum Director Kristina Foss.
Part of the goal of the project is to get rid of the water damage caused by the moisture inside the crypt.
"The beams in the crypt are disintegrating and need to be replaced. So this will be the final piece of retrofitting on Mission Santa Barbara," added Foss.
The Santa Barbara Mission underwent earthquake retrofitting in the 1990's, but the crypt remained untouched. Until now.
Channel Coast Corp. has worked on several missions around the state, but this project is different. The workers have just five days to get it done.
"It's very exciting," said CEO Joe Handerhan. "We're going to be working day and night."
That's because work has to be complete before Saturday's church service, scheduled for 2 p.m.
The crypt restoration is part of Save America's Treasures, a program of the National Trust for Historic Preservation that used both federal and private funds.