By Eric Marrapodi and Brian Todd, CNN

Kansas City, Missouri (CNN) - Elder William Walker slipped white booties over his black wing-tip shoes and instructed his guests to do the same as he led them into the newest Mormon temple in the world.

This day was the first chance the public had to see inside the sacred space for the area’s 49,000 Mormons, and it was also one of the last.

On May 6, when Thomas S. Monson, the head of the 14 million member Church of Jesus Christ of Latter-Day Saints, dedicates this temple, the doors will close forever to the public. The church said it expects as many as 100,000 visitors in Kansas City before the temple will be closed to the public.

After that, only temple-recommended Mormons will be able to walk through the heavy wooden and stained-glass doors.

“This is a sacred space, set apart place for only those who are devout followers of the faith,” Walker said.

For Mormons, temples serve as places of contemplation, instruction and worship experiences, like weddings and posthumous baptisms.

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The 67-year-old Walker is the executive director of the Temple Department, and he is the point man for the church’s 137 temples.

Walker is a top official in the LDS church as a member of the First Quorum of the Seventy and he reports directly to Monson. The Canadian-born hockey fanatic has been a lifelong member of the church. He graduated from Brigham Young University, served a Mormon mission to Japan and spent time in the private sector working in securities and investment banking before being called to serve the church full-time in 2002.

Kansas City’s temple is the latest to open. The church has announced it will build 29 temples across five continents. Construction is under way in Paris and Rome, and temples are planned for Peru and South Africa.

“We’re building temples where the church is grown and have a concentration of members,” he said.

Inside the temple the required first stop is the Recommend Desk. After the dedication, only Mormons who have a recommend card are able to enter and participate in worship. The personalized cards are given by local church leaders to adherents who profess to be living in accordance with church teachings.

As he explained the process, Walker reached into his wallet, pushed his Utah driver’s license aside and pulled out his recommend card, which was endorsed by Monson, his bishop. Walker said his credit-card-sized recommend card, like all others, is only good for two years.

CNN was invited by church officials to tour the temple with Walker before its dedication. The church denied CNN's request to film inside the space, saying it was against church policy. The LDS church provided still images after the tour, which accurately depicted key parts of the temple. In a rare move, CNN was permitted to film inside the front of the temple at the Recommend Desk, but no farther.

"It's not about secret. It's about sacred,” Walker said after the tour, making what the church sees as a key distinction. “We feel that it's a very sacred and special place and therefore it is reserved for those worship functions and those ordinances that take place in the temple. It's not about secret."

Walker said the policy is not unlike that for Shinto shrines in Japan, where he served his mission.

But it's a thin line between sacred and secret. Public tours of the temple are only available when they are first built or undergo massive renovations. After that, outsiders and Mormons who are not temple recommended are kept out, even from wedding ceremonies.

In the sealing room, where eternal weddings take place, Walker points out the altar at the center of the room. The bride and groom kneel facing each other and the officiant stands off to the side. The room is richly decorated with Swarovski crystal chandeliers and massive gilded mirrors on either side of the room, and Walker raves about the design on the white carpet, carefully explaining how local artisans cut the meticulous pattern by hand.

Despite the grand size of the building, each room is small: This is the biggest of the three sealing rooms, and its capacity is just 49 people.

Guests are welcome at Sunday worship at one of the church’s 18,000 meeting houses, Walker is quick to note. The temple, he observes, “is a sacred, special place that’s unique. There are only 137 of these temples in all the world.”

The temple also contains a gleaming baptismal font. Though it’s a point of pride for Mormons, it has been controversial elsewhere. A church ceremony called “proxy baptisms” by Mormons includes posthumous baptisms of Jews, some of whom have protested the practice.

However, in Mormon doctrine, baptism is essential for salvation. While converts to the faith are baptized in services at local wards, the weekly meeting place for services open to the public, proxy baptisms take place only in the temple and in private.

The proxy baptisms are supposed to be for Mormons’ ancestors who were not of the faith. Walker said the baptism serves as an invitation to accept Mormonism as an avenue into heaven.

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At the temple, Walker took his visitors through the process as it is supposed to work.

The font rests on 12 oxen, which he said represent the tribes of Israel.

Adherents change into white gowns he jokingly referred to as "jumpsuits," provided by the temple. A male priest leads the proxy into the waist-high water, gives the blessing and the name of the ancestor, then the proxy is lowered into the water, fully immersed, then brought up to the surface. The desk next to the font has a small monitor and a light. That person's job is to record the act for the church's central database.

When the temple begins operation, Walker said, this is a scene that will play out “hundreds of times a day.”

But some Mormons have used the church’s extensive genealogy database to baptize others who are not Mormon ancestors, such as the murdered Jewish reporter Daniel Pearl and holocaust victims like Anne Frank. It’s a practice that has outraged Jewish leaders.

“When people violate the church policy of doing baptisms for those who our leaders have said we’re not going to do that, they’re acting on their own in contradiction of church policy,” he said. “We’re unhappy about that. We love our Jewish friends. We don’t want to offend them or anyone else by our religious practices.”

“We’re sorry. We live by our word and when we say we’re going to do something, we’re going to try and do it,” Walker said.

He promised disciplinary action.

“We’re now tracking those who’ve done this contrary to church policy and we’re going to shut down their access to the church’s database, Family Search, so they can’t do this.”

He acknowledges interest in proxy baptisms, and other Mormon practices, has spiked thanks to Mormon Mitt Romney’s run for president.

While the church takes no position on party politics nor allows its officials to endorse candidates, Walker can see some good coming out of Romney's run for the White House.

“I think it’s perfectly understandable people who are considering him would want to know more about the church he espouses,” he said. “In many ways it may be a good thing that people will want to know more. Maybe some of the old ideas about the church that have persisted in American culture can change.”

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