In another room, the Latter Day Saints perform one of their most controversial rites: "baptisms for the dead."
Members stand in the heated, chlorinated pool and are baptized in the name of their dead ancestors. Those ancestors can be given the option of converting to Mormonism in the afterlife.
"And the people who are deceased, that isn't binding on them," said Cook. "We, in a loving manner, make that available to them and they choose whether or not they want to have it."
But they don't just do this for ancestors of Mormons. Church members have scoured the world, creating a database of hundreds of millions of names, names that are systematically submitted for baptism. This includes, most controversially, Holocaust victims.
"Well, we feel enormous respect for other faiths," said Cook. "And we are just completely respectful of those who suffered during the Holocaust. We just have to make that perfectly clear. And we just see this very differently. We see that in a loving outreach to all the world that we are doing this process of by proxy being baptized for them."
The tour included the ordinance rooms where members make covenants with God to lead worthy lives, and are given the keys that will allow them to enter heaven. This apparently includes secret handshakes, although the apostles didn't care to discuss that.
"We don't get into the details of that," said Ballard.
Cook explained why secrecy is crucial.
"You're going through a process that, if taken out of context, can seem unusual or different, but if you're in the whole, context doesn't seem that way at all," he said.
The apostles prefer to describe the temple as "sacred" rather than "secret." And they point out that, while the 129 temples are members-only, their 18,000 churches and chapels are open to anyone at all.
In fact, the church has 53,000 missionaries out around the world trying to recruit converts to what Mormons believe is the one true Christian church, a church that began in the early 1800s in upstate New York when a teenaged Joseph Smith said he was visited by God and Jesus.
In their early years, the Mormons were violently persecuted.
And it is precisely because of that painful past that critics charge the Mormons with hypocrisy for urging its members, in a letter read from the pulpit in every church in California, to give their money and time to defeat gay marriage in California.
"We were for marriage between a man and a woman because that is the issue that will protect the future of this country and this civilization," said Cook. "It's for the protection of the 5,000-year history of marriage being between a man and a woman."
The Mormons were a large part of a coalition of religions that supported Proposition 8, but they say they are now being unfairly singled out, but that, in some way they are a victim of their own success.
"Well, that's part of it," said Ballard, "but the other part of it is that when something needs to be done, we know how to do it."
And what the leadership wants now, the reason they brought us to the temple, is to be less timid about defending the faith, a faith based on ideas that many people still find hard to believe.
"Yes, it is a big story, it is a big message, but it's true," said Ballard. "We get beat up out there telling it, but so what? We'll keep doing it the best we know how."